Truth About Linux and GPLv2 (in USA)

The truth about Linux and the GPLv2, under USA licensing and property law.(The GPL is revocable by the copyright owner under US licensing law)A license, absent an attached interest, is revocable by the grantor.The reason is because you did not "pay" anything for the "rights" which have been freely allowed.It is only permission to use the property, not a transfer of ownership, and it can be withdrawn at any time by the owner.This differs from commercial copyright licensing contracts where you have paid for the terms in the contract. In commercial copyright, since you now have an attached interest, you have secured the written terms and can enforce them against the other side of the contract (hold them to the bargain).With bare licenses, gratuitous licenses, there is no bargain: only permission which can be withdrawn.

http://www.nicovideo.jp/watch/sm34508909