I have good backlinks, and i rank well on the SERPs (mostly on first page). Does it have anything to do with my site's adsense eCPM?
if you are talking about backlinks to raise pr, then no, they can't increase your ecpm. if you are talking about backlinks from sites that are relevant to your niche, and therefore drive targeted traffic to your site, there might be a slight correlation between backlinks and ecpm. but i'd agree that the niche and the keywords are of primary importance... myspace sites & forums will pretty much never have decent ecpm.