The following comScore Ad Focus ranking for Jan 2015 might be of interest:
http://www.comscore.com/Insights/Market-Rankings/comScore-Ra…
In the buy side networks, Criteo is number 4 in the US, behind Google, Conversant, and Yahoo. Conversant was acquired in Dec 2014 by Alliance Data Systems for $2.4B.
If Criteo keeps performing, it’s likely to be an acquisition candidate. Someone will buy it before it becomes too big. That’s my speculation for the day!
Anirban