thatjen - 11:41 pm on Oct 28, 2011 (gmt 0)

I think I figured out Unmatched Ad Requests are for link units that didn't receive clicks - so it's not something horribly wrong.

What criteria will you use to block ad networks now? I sorted by Ad Request RPM (revenue per thousand) and was going to block the lowest-paying networks (maybe the bottom 25% or bottom 50%), but wasn't sure if this was the best strategy.