The Concept of TrustRank
Researchers from Stanford University and Yahoo! combined forces to come up with a link analysis technique to “semi-automatically” separate useful websites from spammy websites. The idea is that feedback from human reviewers can only go so far and people can only go through so many pages. There has to be another way to distinguish good content from the bad content.
This is where the concept of TrustRank comes in. The basic idea is that established, authoritative sites (like NY Times, WebMD, etc.) will rarely link out to pages that aren’t equally well-regarded. On the other hand, it’s not uncommon to come across webspam that links out to good sites (in very high and unnatural volume), or even name drops in order to trick visitors in an attempt to be a credible source.
The Difference Between Spam and Non-Spam
There are many indicators that can be used to detect spam. Spammy sites will often work in a network where they all link to each other in order to sculpt PageRank and pass link juice to a certain page. Volume of linking out, anchor text, keyword density, black hat techniques (like cloaking) are also indicators of spammy or malicious sites.
Then, there’s the issue of linking C-blocks. Tools like SEOmoz’s Open Site Explorer give you a better idea of the amount of linking C-blocks to your domain. Sites hosted on the same domain may all link to each other in a scheme to gain higher rankings.
To make a long and technical story short, you can think of it like this: Your IP address is where your website resides. The C-block you belong to is your “neighborhood”. If your IP is located in a “bad” C-block, it could be harmful as your site may be associated with spammy sites.
Google’s Official Word?
Although Google doesn’t officially recognize a single page ranking factor of TrustRank, they do acknowledge that the search algorithm takes the concept of trust into consideration. So, it might not be a bad idea after all to think about TrustRank as it can improve your PageRank and overall rankings and reputation.
Have you ever heard this quote? “You are the average of the 5 people you spend the most time with”. Apply that to who your website is associated with and keep good company!