A very notable point from the WebmasterWorld Thread is the likelyhood that the update just affected single word phrases. It matches with our own SERPs and also follows with movement I'm seeing on RankPulse. Cutts further confirms this in a comment he made in his own blog:
Matt Cutts Said,
June 18, 2007 @ 12:31 am
Joost, thanks for the reminder.
Harith: historically speaking, summer is a good time to incorporate ideas into search, but I wouldn’t consider that an update myself. We do always reserve the right to tune our scoring algorithms or change the weight of different factors, even if it only affects a fraction of queries (things such as single-word queries).
feedthebot, I’ve caught up on much of my internal email, but I haven’t tackled external email from the conference yet. That’s high on the list when I can find time this week though. It’s all part of the digging out from vacation + SMX Seattle + SES Toronto process. Is Isla Vista not right?