Is there an official way of knowing when your site has been selected for CPM ads? I'm assuming my site has been, because yesterday it was showing 0 clicks but a few cents in revenue for a short period of time.
Yeah, I'd be interested in knowing that as well. If you browse DP frequently, you will see some different types of adverts, these are CPM ads. However DP is a site which is well known and advertisers will want to put ads here, if you don't run a large and well known site it is unlikely you will have CPM ads.
If you have a small site with low traffic, probably that's not the reason. Maybe it was only a temp error in the stats.
It's finance-related traffic. It could be an error in the stats, but the amount was quite a bit less that I'd normally get per click.