From someone's signature:
GNU GPL: Free as in herpes.
Crude, but funny. Unfortunately, a somewhat accurate analogy.
It seems that I'm averaging about one conversation a week that goes something like "You'd think someone would have solved this problem.... oh, they did.... damnit, it is under the GPL... guess I'll have to re-invent that particular wheel. *sigh*". In almost all of the cases, the individual would have been perfectly happy to contribute their changes or improvements back to the community.
I have long contributed to or written a bunch of software that has been open sourced. Many years ago, I had a serious look at the licensing issues and made the decision to not contribute to GPL'd projects whenever possible. For any project where I could or can choose the license, I have used the MIT license or, more recently, a BSD license.
Part of the reason was because I wanted to ensure that I could use any of my creations in whatever professional context I might be in. This was back in 1995 or so -- I had no idea what might be ahead. Another part of the reason was simply because I didn't want my source wrapped up in some politically driven licensing drama. Why did RMS decide that "license" and "political manifesto" should be synonymous?
From what I have seen, the truly free licenses like BSD, MIT and some forms of the new Creative Commons family of licenses cause the least worry and foster the most innovation. I know many developers that regularly contribute to projects under one of the free license that cannot or will not contribute to GPL'd projects (including LGPL).
Nowadays, I would lean to putting code under Creative Commons Attribution License or simply put code into the Public Domain. SQLite is in the public domain, as an example of a good sized project that has built a successful community with effectively zero licensing considerations.
Funny, if I remember correctly. The original free software community on the Mac and Apple ][ (and, I'm sure other systems-- those were just what I happened to be involved in) was labeled Public Domain. I have no memory of any particular licenses from that era.