It matters absolutely nothing to existing contracts. Nothing at all
Apart from that, GPL3 might/will slow down linux adoption.
Which is just what MS could want. So yes, GPL3 matters maybe some to MS.
Because it will help them
It is going to help Microsoft at least initially if only for the
confusion factor which is going to slow down Linux adoption.
Once GPL3 starts gaining momentum however it is going to be a bad thing
for Microsoft because it closes some of the more nebulous legal loop
holes in GPL2.