Overture rankings are generally pretty good at comparing traffic levels... there is an occasional hiccup sometimes that causes anomalies.... but generally they would be a pretty good barometer.
The numbers update once a month... so if there is a hiccup, it will often get corrected in the following month
You can check relative ranking yourself by going here and typing in different phrases, for example;
Tawnee Stone
http://inventory.overture.com/d/sear...=us&lang=en_US
Jordan Capri
http://inventory.overture.com/d/sear...=us&lang=en_US
The Overture numbers would be affected somewhat depending on which domain the FHG's are on. For example, Traffic Cash Gold hosts all of their FHG's on wannawatch.com and therefore there are people searching for 'wannawatch.com' hoping to find their FHG's
You wouldn't expect wannawatch.com to have much traffic otherwise, as there is no site there... but here are the results for wannawatch.com
http://inventory.overture.com/d/sear...=us&lang=en_US