"Does MS have a history of patent abuse?"

One well known case:

http://en.wikipedia.org/wiki/Stac_Electronics

"Stac, in an effort led by attorney Morgan Chu, sued Microsoft for infringement of two of its data compression patents, and won"

EDIT: So they have a history of sometimes infringing patents, but by abuse perhaps you meant using patents as a weapon?

http://news.cnet.com/8301-13860_3-10206988-56.html - "Microsoft, TomTom settle patent dispute". I am going to have to disagree with you on this one. Some of the patents that MS was beating their war drum over are silly and ignore that the only reason TomTom uses some of these features is to support MS windows users.

I frankly hope they have to payout a half a billion dollars like they did with Eolas so they realize that no software patents is likely cheaper than paying out and paying for lawyers.

Maybe they don't have a story of patent abuse through the courts, probably because they don't want to risk invalidating their patents.

And why bother suing Linux corporate users, most of them also Microsoft users?

Sowing FUD is just as good