lots of people were saying their impressions has went down... well today i saw my ads and now on 790 by 90 had 4 ads unit, now there is only 3 ads unit so per page view 1 impression less that's why impressions has gone down.. hope they put back 4 ads unit on 790 by 90
thats not how it works - each ad block counts as an ad unit impression. if you had 2 different ad units (728x90 and 336x280) then you would have 2 ad impressions per page load. they may have changed it to each page view counts as 1 ad impression (regardless of how many ad units are on the page). this has not been confirmed. jmo