Facebook has become the #1 source of traffic to my blogs, with just a few tiny but targeted Facebook ad campaigns. Interestingly, I'm getting more traffic from Facebook than I am paying for in click charges, and this is distinct from general Facebook traffic which had been fairly stable until I launched my campaigns. It definitely appears as though Facebook ad impressions have good brand awareness building value for the time being.
With Google bringing the volume but at increasing cost to advertisers, and the big G pissing off publishers with periodic revshare land-grabs, it appears that Facebook is going to soon get the attention of large numbers of Google's top 5000 customers who, in their quest for ever more volume of conversions, flock to Facebook like miners to the Goldrush.
For people wanting to simply drive traffic to a site, Facebook advertising is a goldrush in the making. Because of the lack of buying intent inherent in all non-search traffic, however, I think Facebook advertisers will find lots of copper - a valuable metal, yes - but little gold.