>I disagree with this. Software is mostly a product of API flexibility rather than the number of potential users.

I'm filling out a job application that is a Word Document that absolutely vomits when read in OpenOffice. If there were fewer people using Word, they wouldn't be able to get away with that. There's a part of me that doesn't want to work in that sort of shop, but I'm only a year out of college, and if I have to do C# to get a developer position, I'll take that, C# isn't a bad language.

That said, I can't get away with using Linux because of the potential users problem. Now I guess you could call the .doc format an API flexibility problem, but no API is sufficiently flexible that it runs anywhere without testing. There has to be enough of a userbase to justify testing.