Google "Update" - June 27

Google changed its search engine rankings significantly on June 27. It's probably not an actual algorithm change. According to several people on WebmasterWorld it is more likely that Google removed sites from its database entirely, quite possibly by accident.

You can tell if this happenned to your site, by noticing if your traffic fell by a huge amount on June 27 (I have a site where my Google traffic fell 98% -- eg it is 1/50th of what it was before), if when you search for exact rare terms (eg "keyword1 keyword2 keyword3 keyword4" - be sure to use quotations) that your site always appears last or almost last in the rankings, and if when you do a google search for site:www.domain.org your homepage doesn't show up as the first result.

WebmasterWorld Google Discussion

It's possible that Google will reverse this mess, however it might take several months.