My spies tell me there's big changes afoot in San Mateo (and smaller changes in Reading).
Despite the strength of the underlying technology (HP OpenMail, yes I'm biased), Scalix didn't seem to be making its numbers. From the reports of "13 engineers and sales support staff" I imagine that a number of people got made redundant recently.
Xandros and Scalix have been working together for a while now, so I suppose this acquisition makes as much sense as any.
Presumably Scalix now can't get sued by Microsoft for violating Exchange patents? ;-)