Valueclick, Tribalfusion, Casale Statistics-Corelated

[HedgeTex]

I was looking at Alexa statistics on Fastclick, TribalFusion, and CasaleMedia the other day and noticed a strange correlation. The daily reach for all three drops to zero on the same date. I know Valueclick bought Fastclick, but the missing numbers from Fastclick do not aggregate to Mediaplex, AdServer, or any other Valueclick asset.

Could someone help me interpret what could be happening?

Did Alexa change how they track these sites? None of the other tracking cookie advertising URLs show the change though.

Does Live.com coming online have something to do with it? Microsoft's new ad site came online about 30 days after the drop in the others. I know Microsoft was using Yahoo for ads before, but there appears to be some connection between Microsoft, Fastclick, Tribalfusion, and CasaleMedia.

Could Valueclick, TribalFusion, and Casale be joining forces? They would have a better shot competing with Google, Yahoo, and Microsoft if they did.

Is Microsoft beginning to purchase ad networks to better compete with Google and Yahoo?

Am I crazy for giving Alexa statistics too much credit? I think Alexa is useful for trends in large sites.

What do y'all think?

What am I missing?

[HedgeTex]

Correlated