OK, so the title might be over-stating the case just a fraction, but the value of the good old-fashioned display advert is certainly suffering.
A recent comScore study claims that while Facebook and MySpace represent 20% of total US display advertising volume, they only represent 5% of total value. In total, the social networks are depressing average CPMs (cost per thousand impressions).
Social networks are averaging just $0.56 CPM compared to $2.43 average. Take Facebook and friends out of the equation and the CPM rises to $2.99.