There was some interesting numbers served up by Comscore on display advertising this week. The big figure was the amount of ads served to US internet users in Q1. Nearly 1.1 trillion ads were served in the first quarter of the year - a 15.5% rise on last year's figure. The US display market was worth $2.7 billion with an average CPM rate of $2.48. But buried in those numbers you can expect that inventory to be generating a very low yield. Other stats worth noting, included the spectacular growth in volume of ads served by Facebook. It is now serving more ads than Yahoo, but as the WSJ pointed generates considerably less revenue from its availabal inventory. Last year Yahoo made $6.5 from display advertising, while Facebook made just $500 million. I still think it's going to be very difficult for Facebook to generate considerable income from ads placed against its UGC. Facebook is still not a brand safe environment for many many advertisers. [Comscore]