A backlink is a link from one web page to another. An internal link goes to a web page on the same website, while an external link goes to another website.

Link juice is the currency of backlink value. Each link acts as a recommendation or vote. The total value of the link juice that enters a web page attests to its authority or reputation. As long as the receiving page has outbound links, the link juice flows back and is distributed in equal proportions.

Backlinks do not have the same value. Google tells us, through its spokesman Matt Cutts, that the algorithm for determining the link value of a link depends on the reputation of the linking page (PageRank) divided by the number of outbound links. There is a slight reduction needed, otherwise the system would implode.

The number of incoming links to a web page can be determined by searching for ‘link:pageURL’. Results vary for different search engines. Google tends to show a relatively small number, as it only returns links that have a PageRank of at least 3 or 4. My preferred search engine for this purpose is AllTheWeb.com. It would be possible to visit each linked web page and determine its PageRank and number of outgoing links. However, this would be prohibitively time consuming.

Backlink checking programs:

Link Popularity Check – A free program that finds all backlinks to website homepages on AllTheWeb, AltaVista, Bing, Google and Yahoo.

SitePopularity: Find the number of backlinks to a URL (home page or internal page) on Google, Yahoo, AllTheWeb and Altavista. The free version analyzes a maximum of 10 URLs.

BacklinkWatch: This is a free program that finds all the backlinks to a web page and the anchor text, PageRank, and outbound links on the link page. It does not provide any means to calculate the value of each link and no facility to export the data.

SEO SpyGlass – locates all links to a web page in the search engines of your choice. The program then analyzes each inbound link for various factors. By including the PageRank and the total number of outbound links in the linking page, the program will calculate the link value of each incoming link to the web page by dividing the linking page’s PageRank by the total number of outbound links. There is a small reduction as explained above. It is possible to highlight all the data and copy it to a spreadsheet like Excel. The total link value of all incoming backlinks can be determined by summation.

Rank Tracking Programs:

Link Assistant’s Rank Tracker – This program finds the top web page of a website for a list of keywords in search engines selected by the user and records its current position. Changes in ranking over time are presented in tables and graphs.

Those participating in backlinking campaigns should monitor progress with a selection of the above program types. If not, they may be indulging in a potentially wasteful activity.