How many of you guys have this feature enabled? Does it help much? If you don't, why do you have it disabled?
i tried an extended period of time disabled - then and until now enabled. I enjoy a site wide average 2 digits ( eCPM PLUS CTR ) and I instantly feel an UP in eCPM if i have a new site advertiser and I also instantly see a down if one of my site advertisers runs out of ad budget and is off the site for a day or 2. the greater the competition the greater the total revenue. site advertisers also have to BID against and with all global CTR advertisers - even though the mathematics behind CPM-bidding might be more complex - any site-advertiser helps to bring your prices UP. with several k$ / m adsense revenue, a 10-20% more or less easily sums up to a substantial difference ... and that is about the minimum amount a site advertiser brings the $ UP since most use full ad unit ( pics or video ) and hence compete against 4-5 other CTR advertisers.
besides enabling site advertisers - of course you also have to add the "advertise on this site" - link manually to allow POTENTIAL advertisers to find your advertisers-landing page at Google. ( much earlier - last year or so - this link was placed automatically by Google when enabled, now that link has to be added by site owner )