A common argument you’ll hear from mono apologists: “Microsoft doesn’t use patents aggressively”. Let’s take a look at that for a second.

Say you go into a convenience store and you shove a .357 Magnum in the guy’s face and demand his money. You have used a firearm aggressively. It doesn’t really matter that you didn’t pull the trigger – it is still armed robery.

So, when Microsoft command says things like:

We should look at even patenting the things we do add to help Office.

- Bill Gates, 1998

[On being told of the free Star Office]
An interesting development…
At some point we will have to consider the patents they violate.

- Bill Gates, 1998

Maybe we could define the APIs so that they work well with NT and not the others even if they are open. Or maybe we could patent something related to this.

- Bill Gates, 1999

What do we want in cameras for metadata and UI? What do we want relative to device discovery? (hopefully patented stuff).

- Steve Ballmer, 2003

We’ve had an issue, a problem that we’ve had to confront, which is because of the way the GPL works, and because open-source Linux does not come from a company — Linux comes from the community — the fact that that product uses our patented intellectual property is a problem for our shareholders.

- Steve Ballmer, 2006

If a customer says, Look, do we have liability for the use of your patented work? Essentially, If you’re using non-SUSE Linux, then Id say the answer is yes…I suspect that [customers] will take that issue up with their distributor. [Or if customers are considering doing a direct download of a non-SUSE Linux version] theyll think twice about that”

- Steve Ballmer, 2006

If anybody thinks open-source alternatives are free, I guess as they say, you can see me after class. [...] I will tell you that in any comparison that you would do of Windows with Linux, which is an open-source alternative, we will prove to you that when it comes to total cost of ownership our stuff is more economical, whether it’s the other patent-licensing costs that you might have to pay to use open-source software, which is kind of a big unknown right now [...]

- Steve Ballmer, 2007

Then that is Microsoft using patents aggressively.

I’m not sure why some people want to act like just because Microsoft hasn’t done the worst thing possible it means they aren’t doing anything bad at all – but you’ll see this defense a lot from mono apologists (and Microsoft apologists in general, for that matter.)