When we started Criteo, we thought we’d target first websites which don’t have any kind of recommendation system. To our surprise, we found out that our best early adopters were websites which had already implemented an in-house solution or used an existing one. The reason is that those websites had already seen the value of recommendations. We just had to prove them that we had better a predictive accuracy with more features and a fully scalable and robust solution.
If you’re interested in recommendation systems, I encourage you to create an account on criteo.com, so you can compare for yourself. It’s entirely free (for limited use).
We will also launch a whole new batch of recommendation products in a few weeks. We’re currently looking for alpha testers. If you’re interested, please contact me directly by e-mail.

Regarding your idea on sharing identities between websites, we’d love to do that ! But our customers usually don’t want to hear about it.

Thanks again,
Franck Le Ouay
Co-founder & Chief Scientist - CRITEO