Microsoft has been a great partner for Criteo for three years now, since the very early days. I'm therefore really delighted that we've announced our formal partnership in Europe. You can read the details on Microsoft's blog
The full press release is here
Microsoft is the largest publisher in Europe, with strong reach in every market, so I'm particularly pleased that as a result we will be able to further increase the scale of the business we do with them. End result will be that we can send a lot more (converting) users to our advertisers.