A backlink is a link from one webpage to another. An internal link goes to a webpage on the same website whereas 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 link juice coming into a webpage testifies to its authority or reputation. Provided the receiving page has outbound links, the link juice flows out again and is distributed in equal proportions.
Backlinks are not of equal value. Google tells us, through their spokesman Matt Cutts, that the algorithm for determining the link value from a link depends on the reputation of the linking page (PageRank) divided by the number of outbound links. There is a slight necessary reduction otherwise the system would implode.
The number of inbound links to a webpage can be determined by searching for ‘link:pageURL’. The results vary for the different search engines. Google tends to show a relatively small number as it returns only 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 linking webpage and determine its PageRank and number of outbound links. However, this would be prohibitively time consuming.
Backlink Checking Programs:
Link Popularity Check: A free program that finds all the backlinks to website homepages on AllTheWeb, AltaVista, Bing, Google, and Yahoo.
SitePopularity: Finds the number of inbound links to a URL (homepage or internal page) on Google, Yahoo, AllTheWeb and Altavista. The free version looks at a maximum of 10 URLs.
BacklinkWatch: This is a free program that finds all the backlinks to a webpage and the anchor text, PageRank and outbound links on the linking page. It provides no means to calculate the value of each link and no facility to export the data.
SEO SpyGlass: Locates all the links to a webpage on the search engine(s) of your choice. The program then looks at each inbound link for several factors. By including the PageRank and total number of outbound links on the linking page, the program will calculate the link value of each inbound link to the webpage by dividing PageRank of the linking page 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 this into a spread sheet such as Excel. The total link value of all the inbound backlinks can then be determined by summation.
Rank Tracking Programs:
Link Assistant’s Rank Tracker: This program finds the top webpage of a website for a list of keywords on user selected search engines and records its current position. Changes in positioning over time are presented in tables and graphs.
Those engaging in backlinking campaigns should monitor progress with a selection of the above type of programs. Otherwise they may be indulging in potentially uneconomic activity.