vandirk27 - 6:06 am on Nov 16, 2010 (gmt 0)
Thanks for the response. I don't think the bids were a problem, because I even tried raising all keyword bids to a dollar (5 times the average keyword price at the time) and still no ads were served.
However, my impressions appear to be returning to their earlier levels as of tonight, and the latest person I've talked to at AdCenter says that the service has been slow in reflecting changes made to accounts recently.
My impression based on other people's feedback is that AdCenter is having some major system problems related to their import of accounts from a recent merger with Yahoo!