Search engine
optimization (SEO) is the process of improving
the volume and quality of traffic to a web site from search
engines via "natural" ("organic" or
"algorithmic") search results. Usually, the earlier
a site is presented in the search results, or the higher
it "ranks", the more searchers will visit that
site. SEO can also target different kinds of search, including
image search, local search, and industry-specific vertical
search engines.
As a marketing strategy for increasing a site's relevance,
SEO considers how search algorithms work and what people
search for. SEO efforts may involve a site's coding, presentation,
and structure, as well as fixing problems that could prevent
search engine indexing programs from fully spidering a
site. Other, more noticeable efforts may include adding
unique content to a site, ensuring that content is easily
indexed by search engine robots, and making the site more
appealing to users. Another class of techniques, known
as "Black Hat" SEO or spamdexing, use methods
such as link farms and keyword stuffing that tend to harm
search engine user experience. Search engines look for
sites that employ these techniques and may remove their
listings.
The initialism "SEO" can also 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, SEO tactics may be incorporated
into web site development and design. The term "search
engine friendly" may be used to describe web site
designs, menus, content management systems and shopping
carts that are easy to optimize.
| Contents |
| 1 History |
| 2 Webmasters
and search engines |
| a) Getting listings |
| b) Preventing listings |
|
| 3 White hat versus
black hat |
| 4 As a marketing
strategy |
| 5 International
markets |
| 6 Legal precedents |
| 7 See also |
|
| 8 References |
|
| |
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
a webmaster needed to do was submit 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, as well as any 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 earliest known use of the phrase "search
engine optimization" was a spam message posted on
Usenet on July 26, 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 provided a guide to
each page's content. But using meta data to index pages
was found to be less than reliable, because some webmasters
abused meta tags by including irrelevant keywords to artificially
increase page impressions for their website and to increase
their ad revenue. Cost per thousand impressions was at
the time the common means of monetizing content websites.
Inaccurate, incomplete, and inconsistent meta data in
meta tags caused pages to rank for irrelevant searches,
and fail to rank for relevant searches. 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 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. Search engines responded by developing
more complex ranking algorithms, taking into account additional
factors that were more difficult for webmasters to manipulate.
While 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.
Google opens headquarters in Buenos Aires, ArgentinaPage
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, 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 gaining 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.
To reduce the impact of link schemes, as of 2007, search
engines consider a wide range of undisclosed factors for
their ranking algorithms. Google says it ranks sites using
more than 200 different signals. The three leading search
engines, Google, Yahoo and Microsoft's Live Search, do
not disclose the algorithms they use to rank pages. Notable
SEOs, 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.
Webmasters and search engines
By 1997 search engines recognized that some webmasters
were making efforts to rank well in their search engines,
and even manipulating the page rankings in search results.
Early search engines, such as Infoseek, adjusted their
algorithms to prevent webmasters from manipulating rankings
by stuffing pages with excessive or irrelevant keywords.
Due to the high marketing value of targeted search results,
there is potential for an adversarial relationship between
search engines and SEOs. In 2005, an annual conference,
AIRWeb, Adversarial Information Retrieval on the Web,[13]
was created to discuss and minimize the damaging effects
of aggressive web content providers.
SEO companies that employ overly aggressive techniques
can get their client websites banned from the search results.
In 2005, the Wall Street Journal profiled a company, Traffic
Power, that allegedly used high-risk techniques and failed
to disclose those risks to its clients. Wired magazine
reported that the same company sued blogger 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 and seminars. In fact, with the advent of
paid inclusion, some search engines now have a vested
interest in the health of the optimization community.
Major search engines provide information and guidelines
to help with site optimization. Google has a Sitemaps
program to help webmasters learn if Google is having any
problems indexing their website and also provides data
on Google traffic to the website. Yahoo! Site Explorer
provides a way for webmasters to submit URLs, determine
how many pages are in the Yahoo! index and view link information.
Getting listings
The leading search engines, Google, Yahoo! and Microsoft,
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. Yahoo's paid inclusion program has drawn criticism
from advertisers and competitors. Two major directories,
the Yahoo Directory and the Open Directory Project both
require manual submission and human editorial review.
Google offers Google Sitemaps, for which an XML type 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.
Preventing listings
Main article: Robots Exclusion Standard
To avoid undesirable search listings, 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.
White hat versus black hat
SEO techniques are classified by some into two broad categories:
techniques that search engines recommend as part of good
design, and those techniques that search engines do not
approve of and attempt to minimize the effect of, referred
to as spamdexing. Some industry commentators classify
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 will eventually
be banned once the search engines discover what they are
doing.
A SEO tactic, technique or method 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 game the algorithm. 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
Eye tracking studies have shown that searchers scan a
search results page from top to bottom and left to right
(for left to right languages), looking for a relevant
result. Placement at or near the top of the rankings therefore
increases the number of searchers who will visit a site.
However, more search engine referrals does not guarantee
more sales. SEO is not necessarily an appropriate strategy
for every website, and other Internet marketing strategies
can be much more effective, depending on the site operator's
goals. A successful Internet marketing campaign may drive
organic search results to pages, but it also may involve
the use of paid advertising on search engines and other
pages, building high quality web pages to engage and persuade,
addressing technical issues that may keep search engines
from crawling and indexing those sites, setting up analytics
programs to enable site owners to measure their successes,
and improving a site's conversion rate.
SEO may generate a 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. According to notable technologist Jakob Nielsen,
website operators should liberate themselves from dependence
on search engine traffic.[39] A top ranked SEO blog Seomoz.org
has reported, "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
A Baidu search results pageThe 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 held about 40% of the market in the United
States, but Google had an 85-90% market share in Germany.
While there were hundreds of SEO firms in the USA at that
time, there were only about five in Germany.
In Russia the situation is reversed. Local search engine
Yandex controls 50% of the paid advertising revenue, while
Google has less than 9%.[45] In China, Baidu continues
to lead in market share, although Google has been gaining
share as of 2007.
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
In 2002, SearchKing filed suit in an Oklahoma court against
the search engine Google. SearchKing's claim was that
Google's tactics to prevent spamdexing constituted an
unfair business practice. In May 2003, the court pronounced
a summary judgment in Google's favor.
In March 2006, KinderStart.com, LLC filed a First Amendment
complaint against Google and also attempted to include
potential members of the class of plaintiffs in a class
action. The plaintiff's web site was removed from Google's
index prior to the lawsuit and the amount of traffic to
the site plummeted. On March 16, 2007 the United States
District Court 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.
See also
Exclusion standards: robots exclusion standard (robots.txt),
meta elements, nofollow (link attribute)
Related marketing topics: internet marketing, affiliate
marketing, email marketing, display advertising, web analytics
Search marketing related topics: search engine marketing,
social media optimization, paid inclusion, pay per click
(PPC), Google bomb
Search engine spam: spamdexing, web scraping, scraper
site, link farm, Free For All link page
Wikipedia pages: FAQs for Businesses, Wikipedia:Search
engine optimization
Linking: sponsored link, link popularity, link farm, nofollow,
link exchange, reciprocal link, multiway linking, link
exchange network
Other: landing page, IP delivery, Landing page optimization
Major search engines
Google
Yahoo!
Live Search by Microsoft, formerly MSN
Ask.com, formerly Ask Jeeves
SEO organizations
Search Engine Marketing Professional Organization
Notable SEOs
Category:Search engine optimization consultants
SeoStarters.com
Search engine representatives
Dan Crow, Google
Matt Cutts, Google
Adam Lasnik, Google
Jeremy Zawodny, Yahoo!
Gary Price, Ask
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