Headacher > Software patents pose a MUCH greater threat to open source software than does Microsoft IMO
True indeed.
@Dweeber - I know you asked for a reply from Headacher, but I'd like to toss in a picture.
Think of a car. Microsoft owns the most commonly used engine. They invented and built some of its parts, bought some (most?) others, and the remaining engine parts are in the public domain. You and I buy the cars - and pay through the nose for Microsofts engine. (My Lamborghini engine is of course Vector ;-P ). (Now where's the bumper-sticker thread when we need it?)
So the open source community builds a new engine... it's better, faster, cheaper ... but it too may rely on some parts that are owned by others. If these owners don't mind or don't charge an unreasonable fee, then it all works fine.
Now throw a wrench into the works: We build a better engine, but Acme Car Parts Inc., who owns the rights to the newer-style Piston (let's say), has heartburn over us using it for free. So they refuse to let us use it at all - or they want too much for it.
No piston, no engine - and, as they say in Spanish, "no va " which of course means " it doesn't go " and sounds like The Chevy Nova ...

(yes it's a myth)
The more patent infringements, the harder it is to get stuff done openly.
Open Source is really more about Open Rights.