Shooting themselves in the foot..
As the first place most "power-users" will look for an app, is a review site. Ironically though, they may also be doing those users a favour - perhaps reviews will be a little less biased!
On a personal note, I don't begrudge such sites making a commision (they have running costs!), but they piss me off and hit my shit-list when I see them giving outright biased to paid apps or just becoming glorified billboards (Yesss... Downloads and CNET, I'm pointing at you)