Backlink
From Free net encyclopedia
Backlinks are incoming links to a website. The number of backlinks is an indication of the popularity or importance of that website.
Search engines often use the number of backlinks that a website has as one of the factors for determining that website's search engine ranking. For example, Google's PageRank algorithm uses backlinks to help determine a site's rank. To see a site's PageRank, you need to use the Google Toolbar for Microsoft's Internet Explorer, view the bar graph indicating a website's PageRank in Google's website directory, or download the PageRank plugin for Mozilla Firefox.
You can determine the approximate number of backlinks a website has when doing a search at Google by adding "link:" before the website's URL. For example, here is the Google search for "wikipedia.org": [1].
Technical implementations
When HTML was designed, there was no explicit mechanism in the design to keep track of backlinks in software, as this carried additional logistical and network overhead. While Google does keep track of some HTML backlinks, the data can be delayed by hours or months, and backlink data is not kept for pages that Google doesn't watch, such as password-protected areas or dynamic pages.
Some website software internally keeps track of backlinks. Examples of this include most wiki and CMS software.
Other mechanisms have been developed to track backlinks between disparate webpages controlled by organizations that aren't associated with each other. The most notable example of this is TrackBacks between blogs.