Which day of the week do your contextual PPC ads  get the most clicks?
Infolinks  recently released a study showing that in-text pay-per-click advertisements get more clicks on Tuesday than any other day of the week, followed by Wednesday and then Monday. Unsurprisingly, clicks were lowest on Friday, Saturday, and Sunday, with a typical Sunday accounting for 45% fewer clicks than Tuesday.
This study was based on Infolinks' database of over 40,000 websites and analyzed data spanning all of 2010.
According to the study: "Advertisers and publishers can utilize this click data for smarter investments and also higher payouts. By concentrating advertising efforts on Tuesday, Wednesday and even Monday, higher engagement can be accomplished and in turn higher revenue earned."