Are vows not to remove rights legally binding?
<p>Part of the GPL license is that the owner of the copyright can never take back distribution rights (un license the work).</p>

<p>Is  this legally valid or is it similar to any other "free promise" ("I promise to give you a million dollars" isn't binding while "I'll give you a million dollars for this car which I'm taking now").</p>

<p>Under common law, a gratuitous license grant is revocable, one that forms part of a contract is not.</p>

<p>Whether the license is a contract or not turns on a number of things; the most relevant being if there was an intention on both parties to create a contract (which would be demonstrated by their actions) and if consideration passed from the receiver to the giver of the license.</p>

<p>The GPL probably <strong>is</strong> a contract because by giving it and the receiver acting on it they have both demonstrated intention and the receiver has given consideration: a promise to redistribute on the same terms. As such it would be irrevocable.</p>

contract-law