numnum - 11:09 pm on Oct 27, 2011 (gmt 0)
Right, probably not throttling but rather many different factors adding up to what only looks like throttling. That 336X280 ad is the last of three Adsense ads in my HTML, which might account for an erratic CPC (not enough advertisers some days to bid up for that third ad box -- if that's how it works). But it doesn't really explain an unusually high CTR just for that ad box coupled with the unusually low CPC. That's a head scratcher.