e-Marketer downgrades estimates for Social Media Advertising

No surprises there then, as they note:

eMarketer has revised its US social network ad spending projections, estimating that advertisers will spend $1.4 billion to place ads on online social networks this year, down from the previous projection of $1.6 billion.

And whay the downgrade?

Today's economy, combined with the fact that social networks are still trying to come up with successful ad models, has led to lowered ad spending projections for the next few years....

....The challenge is that all of these new forms of advertising are more difficult to plan, measure and quantify than what advertisers are used to, and that has impacted spending growth.

It is indeed far harder than traditional media - and there are few benchmarks, examples of good practice etc. The types of people attending London's MeasurementCamp tells you this is a major issue.

I note that the total global value of all Social Media advertising in 2011 is $3.8bn. I wonder how Facebook's going to make the rest of its money to justify that $15bn valuation then?