A new WebmasterWorld thread is theorizing a new Google filter, currently coined, "google 2 kw filter." Now, this is what several Webmasters are reporting:
- 2 kw term
- used to rank very high, now vanished
- with " "'s returns to high rank
- does not affect rankings for other terms on same site
- home page involved
- only happens on google, still rank high on Y/MSN
- appears on only specific but changing data centers
- long standing site
- Without quotes main keywords gone.
- With quotes, main keywords appear in normal positions
I have not validated any of this but there is a three page WebmasterWorld thread with many folks discussing this new Google filter.
Forum discussion at WebmasterWorld.

Comments:
Forest Wander
09/26/2006 08:25 pm
I would like to utilize such a tool for my site. How can I get it?
Greg
02/07/2007 12:36 pm
Some of the filters are good to hear about. Based on that knowledge I can decide to not get a URL with two+ hyphens or to not pay someone to submit my site to 500 directories. This one to me just seems arbitrary.
Barry Schwartz
02/07/2007 12:55 pm
Greg, look at the date of this article.