• by Joe Mandese , May 8, 2009

According to Jordan Rohan, it’s the fact that a big share of online users are shifting the time they spend with the major online portals to the big social networks. The problem, he says, is that social networks still command only a fraction of the advertising value of the major online portals (see table below, for Rohan’s CPM estimates).

The shift, he says, could lead to “about a billion dollars worth of Internet advertising being gone.”

Ouch.

One thing Rohan believes could help, at least from a market valuation point-of-view, would be if Facebook would finally go public. At the very least, he said, it would get the stock market going for online stock, and especially for social networks.

Major Portals CPMs

Yahoo $8.44

MSN $9.68

AOL $13.58

Social Network CPMs

Facebook. $0.60

Myspace: $1.36