After a couple of months of beta testing by a select number of European ATDs and exchange traders, Microsoft has announced that its exchange is now open for business in the UK and the Netherlands - with plans to roll it out in Germany and France later in the year. Once it goes European-wide, the Microsoft ad exchange will be the biggest real-time premium buying point for traders in this market. It is being welcomed by many in the industry.

ATDs and specialist buyers are now attracting more brand budget - and have been asking for more premium inventory to be put in the automated channel. This market might be liquid - but it still has a long way to go in addressing the brand safe concerns of some high-end brand advertisers. Adx does tick the box on the audience targeting but will never satisfy the contextual requirements of some brands. This move is also being seen by many in the data-driven display space as a necessary counter-weight to the growing influence of Google.

While the Admeld deal was made solely on its share of the US premium publisher market, European buy and sell side players are of the opinion that no one vendor should be allowed to lock down premium dynamic supply. A diversified market is necessary - no, make that an absolute requisite - for all stakeholders in the European exchange space.

Microsoft also announced that traders will be able to buy mobile app inventory through RTB. With Adx on the cusp of making Admob inventory RTB-enabled, are we likely to see a growth spurt in the real-time mobile market? Someone really needs to explain to me how mobile RTB is going to work without a universal cookie on mobile.

Online display impressions available on the market will include Windows Live and MSN non-guaranteed PC inventory initially. Microsoft is also looking to add third-party publishers to the exchange in the year. There could be an awful lot of publisher pitches looking to aggregate supply in the coming months given what Google, GroupM and now Microsoft are looking to build out. The real-time marketplace is getting very interesting.