This is less true every day. Facebook-specific companies like Zynga, Playdom, etc. have huge ad spends on Facebook. Facebook ads are also valuable for highly

This is less true every day. Facebook-specific companies like Zynga, Playdom, etc. have huge ad spends on Facebook. Facebook ads are also valuable for highly localized companies like Groupon, because you get fine-grained demographic control. The CPC of Facebook ads has probably risen by 50-60% over the last year, and it's only going up.