The recent Google Vince update has many speculating on the cause of the impact to search rankings. In my opinion, Google has tweaked a knob on what is known as the TSTR or Topic Sensitive Trust Rank. The TSTR involves a human element to determine seed pages that can distribute trust and authority to topically related websites.

Where do these seed pages come from?

It appears that many of the “seeded” pages come from the Yahoo Directory. Lets compare search results for “airline tickets” in Google and in the Yahoo Directory.

Google results airline tickets                   Yahoo Directory

date  2009-3-16

1. orbitz                                                   1. travelocity.com
2. travelocity.com                                       2. orbitz.com
3. priceline.com                                          3. aa.com
4. cheaptickets.com                                    4. expedia.com
5. nwa.com                                               5. cheapflights.com
6. aa.com                                                  6. priceline.com
7. kayak.com                                              7. usairways.com
8. allcheapfares.com                                    8. hotwire.com
9. delta.com                                               9. nwa.com
10. cheapflights.com                                   10. united.com

This current comparison between these two sets is significant because prior to February 2009, the following two sites didn’t rank in the top ten Google search results for “airline tickets”.

aa.com
nwa.com

Besides these new two urls to Google’s top ten, notice the number of matches between the two sets?

The Yahoo Directory is likely considered high-quality due to the entrance fee of $299 for each web site submitted to it. The high up-front cost tends to keep out the riff-raff. Submitters also have to agree to the terms of service and undergo a review by an editorial staff.

The Yahoo Directory appears to be very helpful in adding to a site’ s trust.

Graphic from the Google “Trust Rank” Patent: