Well, I'm not making a moral argument. I did imply that it was "a slightly shady business practice". Clearly, Google is using money from its search business to fund OS development, and to undercut competitors. I do have a bit of a problem with that.

But I don't think it's as problematic as using patents to go after your competition. Like I said, offering something for free makes it harder to compete with you, but not impossible. Lots of companies compete with free alternatives. Twitter clearly isn't the only example. Desktop operating systems, word processors, text editors, pick whichever example you prefer.

Owning the right patents, on the other hand, can make it impossible for others to compete with you (e.g. what's happening to HTC right now).