I read this very interesting blog about how Social Media Comprises 20% of All US Display Ad Impressions as per Comscore data.

http://blog.searchenginewatch.com/090901-125314

So I predict this will increase in due time.

Print ads went on life support because of banner ads, banner ads went on the critical list because of social media. In both cases what grew big whithered on the vine and what took its place was doomed to the same fate eventually. So will be the case with social media ads. But right now, like you, I see there prevalence growing daily.

I just wonder in the near future, what will take over social media ads. I don't know yet. Does anyone have any predictions?

I predict that everyone who is tweeting and updating their facebook profiles using web-enabled phones will develop eye problems and recurring headache issues. Their doctors will tell them to get away from the little screens (and probably all screens) and read printed word again. We will then have a retro-print ad revolution.
Of course, I could be wrong!