Personally, I MIT/BSD my stuff because, well... it means I don't have to think about it ever again. If I do GPL, I have to make sure that I'm following the rules set out in that license and making sure others who have based their code on my project have done the same.
And that's, like, work, man, especially if you don't have a foundation and legal eagles on your side to double-check that everything's kosher.
Linux is an exception, not a rule, in how GPL is usually handled in FLOSS projects.