It prevents the "original" author from making those versions unless he or she requests a transfer of copyright for any outside code. If you have evidence of the second claim, I'd love to see it or see a link. (I mean this as non-confrontationally as possible; I don't have an opinion one way or the other on whether it's true, but now I'm curious.)
Re:Atom Is Now Open Source
by bryanlarsen on Tuesday May 06, 2014 @01:20PM
(#7705819)
The standard example of this practice is MySQL. If you want some more, Google for "open core". Warning: you'll probably run into many heated arguments.
Re: the heated arguments, exactly the reason for my parenthetical comment earlier :). Thanks for the pointer.
> GPL [...] prevents anybody but the original author from making those pro versions.
This is only true as long as they accept no 3rd party contribution. In this case, accepting 3rd party modules is a crucial feature, so GPL+commercial wouldn't fly.
Re:Atom Is Now Open Source
by pervycreeper on Tuesday May 06, 2014 @05:10PM
(#7707104)
Yes, but in that case the "pro" versions, at least, are not parasitic on some other author's work
Therefore companies who want to make their money selling pro versions usually choose the GPL license. So in practice, we see more "commercial/pro" versions of GPL software than we do of MIT/BSD licensed software.