Only 6% of developers working on Open Source software have adopted GPLv3, according to Evans Data Corp's recently released Open Source Software Development Survey. Two-thirds say they will not be adopting GPLv3 anytime in the next year, and 43% say they will never implement the new license. In addition, almost twice as many would be less likely to join a project that implements GPLv3 than would be more likely to join.
"GPLv3 is controversial because it imposes restrictions on what you can do with programs implemented under this license," said John Andrews, President and CEO of Evans Data Corp. "Developers are confused and divided about those restrictions, with fairly equal numbers agreeing with the restrictions, disagreeing with them, or thinking they will be unenforceable."
http://biz.yahoo.com/bw/070925/20070925006182.html?.v=1