It seems that Microsoft are embracing Big Data whole heartedly​ and looking at ways they can get an edge over the competition. Big Data in memory could give them that.

​http://blogs.technet.com/b/dataplatforminsider/archive/2012/04/09/the-coming-in-memory-database-tipping-point.aspx

http://www.microsoft.com/sqlserver/en/us/solutions-technologies/data-warehousing/pdw.aspx