edinburgher - 7:55 am on Jan 9, 2013 (gmt 0)
After a couple of improving days Tuesday was a pit of despair. Good pageviews, slightly low CTR, awful CPC. It's as if all the (relatively) high CPC clicks are missing.
I've long suspected higher CPC clicks go through extra filters, probably on dedicated servers. My figures for yesterday are consistent with problems on these hypothetical high-click servers.