There is no need for the 300-plus ad networks out there. As a result, the stronger networks are picking up funding to shore up their positions and the weaker ones are getting bought. Just last night, for instance, Glam Media bought AdaptiveAds. This morning SocialMedia raised $6 million rather than the initial $20 million it was looking for and mobile ad network AdMob raised $12.5 million.

Ad network CPMs were down in Q4 ’08 compared with Q4 ’07, according to PubMatic.  Cost-per-thousand ad impressions for online publishers are generally off about 20%, according to several people on both the buying and selling side, and sell-through rates are dropping, according to AdvertisingAge.