Search Engine Optimization
Search engine optimization (SEO) is the
process of improving the visibility of a website or a web page in search
engines via the “natural” or un-paid (“organic” or “algorithmic”)
search results. In general, the earlier (or higher ranked on the search
results page), and more frequently a site appears in the search results
list, the more visitors it will receive from the search engine’s users.
SEO may target different kinds of search, including image search, local
search, video search, academic search,[1] news search and
industry-specific vertical search engines.
As an Internet marketing strategy, SEO
considers how search engines work, what people search for, the actual
search terms or keywords typed into search engines and which search
engines are preferred by their targeted audience. Optimizing a website
may involve editing its content and HTML and associated coding to both
increase its relevance to specific keywords and to remove barriers to
the indexing activities of search engines. Promoting a site to increase
the number of backlinks, or inbound links, is another SEO tactic.
The acronym “SEOs” can refer to “search engine optimizers,” a term
adopted by an industry of consultants who carry out optimization
projects on behalf of clients, and by employees who perform SEO services
in-house. Search engine optimizers may offer SEO as a stand-alone
service or as a part of a broader marketing campaign. Because effective
SEO may require changes to the HTML source code of a site and site
content, SEO tactics may be incorporated into website development and
design. The term “search engine friendly” may be used to describe
website designs, menus, content management systems, images, videos,
shopping carts, and other elements that have been optimized for the
purpose of search engine exposure.
History
Webmasters and content providers began
optimizing sites for search engines in the mid-1990s, as the first
search engines were cataloging the early Web. Initially, all webmasters
needed to do was submit the address of a page, or URL, to the various
engines which would send a “spider” to “crawl” that page, extract links
to other pages from it, and return information found on the page to be
indexed. The process involves a search engine spider downloading a page
and storing it on the search engine’s own server, where a second
program, known as an indexer, extracts various information about the
page, such as the words it contains and where these are located, as well
as any weight for specific words, and all links the page contains,
which are then placed into a scheduler for crawling at a later date.
Site owners started to recognize the
value of having their sites highly ranked and visible in search engine
results, creating an opportunity for both white hat and black hat SEO
practitioners. According to industry analyst Danny Sullivan, the phrase
“search engine optimization” probably came into use in 1997. The first
documented use of the term Search Engine Optimization was John Audette
and his company Multimedia Marketing Group as documented by a web page
from the MMG site from August, 1997.
Early versions of search algorithms
relied on webmaster-provided information such as the keyword meta tag,
or index files in engines like ALIWEB. Meta tags provide a guide to each
page’s content. Using meta data to index pages was found to be less
than reliable, however, because the webmaster’s choice of keywords in
the meta tag could potentially be an inaccurate representation of the
site’s actual content. Inaccurate, incomplete, and inconsistent data in
meta tags could and did cause pages to rank for irrelevant
searches.[unreliable source?] Web content providers also manipulated a
number of attributes within the HTML source of a page in an attempt to
rank well in search engines.
By relying so much on factors such as
keyword density which were exclusively within a webmaster’s control,
early search engines suffered from abuse and ranking manipulation. To
provide better results to their users, search engines had to adapt to
ensure their results pages showed the most relevant search results,
rather than unrelated pages stuffed with numerous keywords by
unscrupulous webmasters. Since the success and popularity of a search
engine is determined by its ability to produce the most relevant results
to any given search, allowing those results to be false would turn
users to find other search sources. Search engines responded by
developing more complex ranking algorithms, taking into account
additional factors that were more difficult for webmasters to
manipulate.[original research?]
Graduate students at Stanford
University, Larry Page and Sergey Brin, developed “Backrub,” a search
engine that relied on a mathematical algorithm to rate the prominence of
web pages. The number calculated by the algorithm, PageRank, is a
function of the quantity and strength of inbound links. PageRank
estimates the likelihood that a given page will be reached by a web user
who randomly surfs the web, and follows links from one page to another.
In effect, this means that some links are stronger than others, as a
higher PageRank page is more likely to be reached by the random surfer.
Page and Brin founded Google in 1998.
Google attracted a loyal following among the growing number of Internet
users, who liked its simple design. Off-page factors (such as PageRank
and hyperlink analysis) were considered as well as on-page factors (such
as keyword frequency, meta tags, headings, links and site structure) to
enable Google to avoid the kind of manipulation seen in search engines
that only considered on-page factors for their rankings. Although
PageRank was more difficult to game, webmasters had already developed
link building tools and schemes to influence the Inktomi search engine,
and these methods proved similarly applicable to gaming PageRank. Many
sites focused on exchanging, buying, and selling links, often on a
massive scale. Some of these schemes, or link farms, involved the
creation of thousands of sites for the sole purpose of link spamming.
By 2004, search engines had incorporated
a wide range of undisclosed factors in their ranking algorithms to
reduce the impact of link manipulation. Google says it ranks sites using
more than 200 different signals. The leading search engines, Google,
Bing, and Yahoo, do not disclose the algorithms they use to rank pages.
SEO service providers, such as Rand Fishkin, Barry Schwartz, Aaron Wall
and Jill Whalen, have studied different approaches to search engine
optimization, and have published their opinions in online forums and
blogs. SEO practitioners may also study patents held by various search
engines to gain insight into the algorithms.
In 2005, Google began personalizing
search results for each user. Depending on their history of previous
searches, Google crafted results for logged in users. In 2008, Bruce
Clay said that “ranking is dead” because of personalized search. It
would become meaningless to discuss how a website ranked, because its
rank would potentially be different for each user and each search.
In 2007, Google announced a campaign against paid links that transfer
PageRank. On June 15, 2009, Google disclosed that they had taken
measures to mitigate the effects of PageRank sculpting by use of the
nofollow attribute on links. Matt Cutts, a well-known software engineer
at Google, announced that Google Bot would no longer treat nofollowed
links in the same way, in order to prevent SEO service providers from
using nofollow for PageRank sculpting. As a result of this change the
usage of nofollow leads to evaporation of pagerank. In order to avoid
the above, SEO engineers developed alternative techniques that replace
nofollowed tags with obfuscated Javascript and thus permit PageRank
sculpting. Additionally several solutions have been suggested that
include the usage of iframes, Flash and Javascript.
In December 2009, Google announced it
would be using the web search history of all its users in order to
populate search results.
Google Instant, real-time-search, was introduced in late 2009 in an
attempt to make search results more timely and relevant. Historically
site administrators have spent months or even years optimizing a website
to increase search rankings. With the growth in popularity of social
media sites and blogs the leading engines made changes to their
algorithms to allow fresh content to rank quickly within the search
results.
Relationship with search engines
Yahoo and Google offices
By 1997, search engines recognized that
webmasters were making efforts to rank well in their search engines, and
that some webmasters were even manipulating their rankings in search
results by stuffing pages with excessive or irrelevant keywords. Early
search engines, such as Altavista and Infoseek, adjusted their
algorithms in an effort to prevent webmasters from manipulating
rankings.
Due to the high marketing value of targeted search results, there is
potential for an adversarial relationship between search engines and SEO
service providers. In 2005, an annual conference, AIRWeb, Adversarial
Information Retrieval on the Web, was created to discuss and minimize
the damaging effects of aggressive web content providers.
Companies that employ overly aggressive
techniques can get their client websites banned from the search results.
In 2005, the Wall Street Journal reported on a company, Traffic Power,
which allegedly used high-risk techniques and failed to disclose those
risks to its clients. Wired magazine reported that the same company sued
blogger and SEO Aaron Wall for writing about the ban. Google’s Matt
Cutts later confirmed that Google did in fact ban Traffic Power and some
of its clients.
Some search engines have also reached
out to the SEO industry, and are frequent sponsors and guests at SEO
conferences, chats, and seminars. Major search engines provide
information and guidelines to help with site optimization. Google has a
Sitemaps program [dead link] to help webmasters learn if Google is
having any problems indexing their website and also provides data on
Google traffic to the website. Bing Toolbox provides a way from
webmasters to submit a sitemap and web feeds, allowing users to
determine the crawl rate, and how many pages have been indexed by their
search engine.
Methods
Getting indexed
The leading search engines, such as Google, Bing and Yahoo!, use
crawlers to find pages for their algorithmic search results. Pages that
are linked from other search engine indexed pages do not need to be
submitted because they are found automatically. Some search engines,
notably Yahoo!, operate a paid submission service that guarantee
crawling for either a set fee or cost per click. Such programs usually
guarantee inclusion in the database, but do not guarantee specific
ranking within the search results.[dead link] Two major directories, the
Yahoo Directory and the Open Directory Project both require manual
submission and human editorial review. Google offers Google Webmaster
Tools, for which an XML Sitemap feed can be created and submitted for
free to ensure that all pages are found, especially pages that aren’t
discoverable by automatically following links.
Search engine crawlers may look at a
number of different factors when crawling a site. Not every page is
indexed by the search engines. Distance of pages from the root directory
of a site may also be a factor in whether or not pages get crawled.
Additionally, search engines sometimes have problems with crawling sites
with certain kinds of graphic content, flash files, portable document
format files, and dynamic content.
Preventing crawling
Main article: Robots Exclusion Standard
To avoid undesirable content in the search indexes, webmasters can
instruct spiders not to crawl certain files or directories through the
standard robots.txt file in the root directory of the domain.
Additionally, a page can be explicitly excluded from a search engine’s
database by using a meta tag specific to robots. When a search engine
visits a site, the robots.txt located in the root directory is the first
file crawled. The robots.txt file is then parsed, and will instruct the
robot as to which pages are not to be crawled. As a search engine
crawler may keep a cached copy of this file, it may on occasion crawl
pages a webmaster does not wish crawled. Pages typically prevented from
being crawled include login specific pages such as shopping carts and
user-specific content such as search results from internal searches. In
March 2007, Google warned webmasters that they should prevent indexing
of internal search results because those pages are considered search
spam.
Increasing prominence
A variety of methods can increase the prominence of a webpage within the
search results. Cross linking between pages of the same website to
provide more links to most important pages may improve its visibility.
Writing content that includes frequently searched keyword phrase, so as
to be relevant to a wide variety of search queries will tend to increase
traffic. Updating content so as to keep search engines crawling back
frequently can give additional weight to a site. Adding relevant
keywords to a web page’s meta data, including the title tag and meta
description, will tend to improve the relevancy of a site’s search
listings, thus increasing traffic. URL normalization of web pages
accessible via multiple urls, using the “canonical” meta tag or via 301
redirects can help make sure links to different versions of the url all
count towards the page’s link popularity score.
Image search optimization
Image search optimization is the process
of organizing the content of a webpage to increase relevance to a
specific keyword on image search engines. Like search engine
optimization, the aim is to achieve a higher organic search listing and
thus increasing the volume of traffic from search engines.
Image search optimization techniques can be viewed as a subset of search
engine optimization techniques that focuses on gaining high ranks on
image search engine results.
Unlike normal SEO process, there isn’t much to do for ISO. Making high
quality images accessible to search engines and providing some
description about images is almost all that can be done for ISO.
White Hat Versus Black Hat
SEO techniques can be classified into
two broad categories: techniques that search engines recommend as part
of good design, and those techniques of which search engines do not
approve. The search engines attempt to minimize the effect of the
latter, among them spamdexing. Industry commentators have classified
these methods, and the practitioners who employ them, as either white
hat SEO, or black hat SEO. White hats tend to produce results that last a
long time, whereas black hats anticipate that their sites may
eventually be banned either temporarily or permanently once the search
engines discover what they are doing.
An SEO technique is considered white hat
if it conforms to the search engines’ guidelines and involves no
deception. As the search engine guidelines are not written as a series
of rules or commandments, this is an important distinction to note.
White hat SEO is not just about following guidelines, but is about
ensuring that the content a search engine indexes and subsequently ranks
is the same content a user will see. White hat advice is generally
summed up as creating content for users, not for search engines, and
then making that content easily accessible to the spiders, rather than
attempting to trick the algorithm from its intended purpose. White hat
SEO is in many ways similar to web development that promotes
accessibility, although the two are not identical.
Black hat SEO attempts to improve
rankings in ways that are disapproved of by the search engines, or
involve deception. One black hat technique uses text that is hidden,
either as text colored similar to the background, in an invisible div,
or positioned off screen. Another method gives a different page
depending on whether the page is being requested by a human visitor or a
search engine, a technique known as cloaking.
Search engines may penalize sites they
discover using black hat methods, either by reducing their rankings or
eliminating their listings from their databases altogether. Such
penalties can be applied either automatically by the search engines’
algorithms, or by a manual site review. One infamous example was the
February 2006 Google removal of both BMW Germany and Ricoh Germany for
use of deceptive practices. Both companies, however, quickly apologized,
fixed the offending pages, and were restored to Google’s list.
As A Marketing Strategy
SEO is not an appropriate strategy for
every website, and other Internet marketing strategies can be more
effective, depending on the site operator’s goals. A successful Internet
marketing campaign may also depend upon building high quality web pages
to engage and persuade, setting up analytics programs to enable site
owners to measure results, and improving a site’s conversion rate.
SEO may generate an adequate return on
investment. However, search engines are not paid for organic search
traffic, their algorithms change, and there are no guarantees of
continued referrals. Due to this lack of guarantees and certainty, a
business that relies heavily on search engine traffic can suffer major
losses if the search engines stop sending visitors. Search engines can
change their algorithms, impacting a website’s placement, possibly
resulting in a serious loss of traffic. According to Google’s CEO, Erick
Schmidt, in 2010, Google made over 500 algorithm changes – almost 1.5
per day. It is considered wise business practice for website operators
to liberate themselves from dependence on search engine traffic.
Seomoz.org has suggested that “search marketers, in a twist of irony,
receive a very small share of their traffic from search engines.”
Instead, their main sources of traffic are links from other websites.
International Markets
Optimization techniques are highly tuned
to the dominant search engines in the target market. The search
engines’ market shares vary from market to market, as does competition.
In 2003, Danny Sullivan stated that Google represented about 75% of all
searches. In markets outside the United States, Google’s share is often
larger, and Google remains the dominant search engine worldwide as of
2007. As of 2006, Google had an 85-90% market share in Germany. While
there were hundreds of SEO firms in the US at that time, there were only
about five in Germany. As of June 2008, the marketshare of Google in
the UK was close to 90% according to Hitwise. That market share is
achieved in a number of countries.
As of 2009, there are only a few
large markets where Google is not the leading search engine. In most
cases, when Google is not leading in a given market, it is lagging
behind a local player. The most notable markets where this is the case
are China, Japan, South Korea, Russia and the Czech Republic where
respectively Baidu, Yahoo! Japan, Naver, Yandex and Seznam are market
leaders.
Successful search optimization for international markets may require
professional translation of web pages, registration of a domain name
with a top level domain in the target market, and web hosting that
provides a local IP address. Otherwise, the fundamental elements of
search optimization are essentially the same, regardless of language.
Legal Precedents
On October 17, 2002, Search King filed
suit in the United States District Court, Western District of Oklahoma,
against the search engine Google. SearchKing’s claim was that Google’s
tactics to prevent spamdexing constituted a tortious interference with
contractual relations. On May 27, 2003, the court granted Google’s
motion to dismiss the complaint because SearchKing “failed to state a
claim upon which relief may be granted.”
In March 2006, KinderStart filed a
lawsuit against Google over search engine rankings. Kinderstart’s
website was removed from Google’s index prior to the lawsuit and the
amount of traffic to the site dropped by 70%. On March 16, 2007 the
United States District Court for the Northern District of California
(San Jose Division) dismissed KinderStart’s complaint without leave to
amend, and partially granted Google’s motion for Rule 11 sanctions
against KinderStart’s attorney, requiring him to pay part of Google’s
legal expenses.
