thecityofgold2005 - 12:14 pm on May 3, 2007 (gmt 0)

In my sector several sites have been intermittently popping in and out of the top 10 for several months, my own site included. In fact, of the recent 'usual' top-ten it has happened to 6 different sites. The length of time out varies from almost none to several days and different datacentres show different sites out at the same time.

I can only guess, based on what Matt Cutts has said, that this is some sort of paid link / repetitive anchor text filter. The yo-yoing is only happening for the key money term and not variations. This would make sense if it was an achor text filter since a lot of the anchor text for these sites is the key money term.

Personally I think Google is pulling sites (or applying this extreme fliter to them) in order to see how many people then search for the site's name in its absense from the regular money term serps. In this way Google could determine how much a site is missed and thus get an idea of how much it deserves the ranking it has. This would all be part of Matt Cutts current crusade against paid links and anchor text based manipulation.