Let's see how well that ad spend holds up when businesses asses the ROI...
There's a lot of tosh talked about it but as SevenCubed referenced above it's a fundamentally different platform.
People on FB aren't in buy mode.
There's no like for like CPC or CTR comparisons. An adwords advert for a product might well convert extremely well for reasons outlined above but the same model be it CPM type or CPC with FB just doesn't work.
Consequently, FB HAS to adjust it's pricing to a level that gives something nearer the same. The problem they have is that to do so is very difficult as it's a very different beast. A CPC model on adwords that charges $1 per click might well need to be closer to 0.01 cents or less on FB, simply due to the poor levels of conversion.
Whilst there's most certainly a value of sorts in being attached to the FB system (pages, likes, positive ID, shares etc) they haven't yet conclusively demonstrated that their ads deliver value anywhere near to what companies are being asked to pay for clicks or CPM. I used it once and spent a paltry $70. I received 10's of 1000's of impressions, impressions that most people were probably either blind to or annoyed by. 807,588 imps 33 clicks CTR 0.004%CPC 1.38 IOW - a waste of time and money on a campaign that was carefully targeted.
Don't get me wrong, there's bundles of edge cases where guerilla tactics for quirky things can be very profitable indeed. Drive by downloads generated by sexy avatars or get rich quick type nonsense on the scuzzy side of the money pond are a few that spring to mind along with those annoying game ads and crap like that, but for genuine mainstream products and services, it just isn't there.
I'm sure somewhere will chime in about brand value and awareness and hidden intangibles but ultimately, they need to demonstrate clear ROI to the many 1000's of businesses who they could potentially sell to,