The addition of Estimated Top Impressions in Google’s Bid Simulator data has elucidated a little recognized effect of Google acting like a competitor with its advertisers within its auctions.

Does it help you, or hurt you when your competitors behave irrationally?

In bidding as in newspaper columns, use caution when using averages to characterize highly skewed or highly dispersed distributions.

Dumb PPC bidding is easy. Smart PPC bidding is hard.