The author's thesis is that Facebook ads are bad because they can't harvest demand the same way Google ads can (no purchasing intent), so once Facebook has exhausted its share of 'gullible' or 'naive' businesses who give ads a try, their profitability will fall like a house of cards.

This is flawed in two important ways:

1. Just because people don't click on banner ads doesn't mean there isn't a place for advertising.

2. Facebook isn't only monetizing with ads. For example, they've proven themselves to be a killer platform for social games and Facebook Credits seems to have a promising future.