jonathanleger - 1:31 pm on Aug 10, 2004 (gmt 0)

I think what we're seeing when this kind of sudden (and sometimes drastic) change occurs is either:

1) the AdWords advertisers had a big advertiser come on with high bids (or a high bidder was lost for those seeing lower EPC)

or

2) Google has done its regular "smart pricing" update based on conversion data (and whatever else they use), and we're seeing the effect of that recalculation.

I tend to lean toward #2 more than #1 since I'm reading more of these kinds of posts since the smart pricing change.