Apparently, Groove was sold to Microsoft for $120 million in cash (via Dave) which falls short of $155 million invested into Groove.  Since Microsoft was the largest investor, it's share out of the $120 million is about $80 million.  That means Microsoft bought rest of Groove for just $40 million.

Groove investors got some of their money back for which founders gained some respect.  Microsoft got a bargain (?!?) and a new CTO.  And employees got nothing for their shares.  Phew!