Most seo experts agree that page rank is no longer a good measure of the quality of an inbound link and that Google is now putting more emphasis on TrustRank when it comes to linking. Still we all know linking is important so how is one to judge. Bob Mutch of SEO Company, with the help of Aaron Wall (SEOBook) and Rand Fishkin (SEOmoz), has developed the concept of an Inbound Link Quality (ILQ) ranking system as a way to provide a measurement of the quality of any given link.
The main idea behind Inbound Link Quality is fairly simple. Sites that have a lot of quality links pointing to them will in turn provide a similar amount of quality to any page they links to. ILQ is thus a measurement based on the amount of links pointing to a given site which originate from dir.yahoo, dmoz.org, .edu, and .gov sites. The two directory sites and sites with the .edu and .gov tld extensions will generally have a good amount of trust and sites with more links from those sites also stand to have a fair amount of trust.
The concept began when Bob was asked to determine which directories would provide the most link benefit. Realizing that there were too many variables involved in determining which directory was better than the next the concept developed into ranking each directory based on inbound links. Bob is the first to admit the system isn’t perfect, but it is a step in the right direction.
You can measure ILQ with the recently released extension for Firefox that will show the inbound link quality of the sites you view in the browser. If you don’t use Firefox there is also an online tool to do the same. A warning though that the online tool is very slow. Opt for the extension if you use Firefox. A similar tool is in the works for IE.
The system is fairly new and Bob is waiting for it to take hold within the seo community before developing the concept and rating system in detail. It’s not a perfect system, but I think it’s on the right track. It still needs to distinguish more between different types of .edu sites for example as a link from the home page of a major university certainly carries more trust with it than the personal home page of a student at a small college and not all universities use the .edu extension. Similarly not all countries use the .gov extension for their government sites. The concept is still sound and I’d like to see how the system and tool evolves.
Bob started threads at several popular seo forums describing the inbound link quality system in greater detail. The discussion in each thread will also help explain the concept in more detail as well as where it might be headed and how those in the seo community would like to see it develop.