[phkahler]

License proliferation was a problem largely supported by the OSI. IMHO there are really only 3 free/open licenses necessary - GPL, LGPL and BSD (or MIT). Anyone else is trying to be open or free while also supporting some other agenda.

If you want it both ways, go dual lincense with GPL and a commercial license. Just be up front and honest about it.

That said, I need to reread GPL3 in detail...

[dredmorbius]

There are a few other variants. Affero, as noted, also the Mozilla Public License, which applies on a file-by-file basis and allows for proprietary code to be integrated into a MozPL licensed work as a whole and distributed.

But otherwise, yes: GPL, LGPL, BSD/MIT are the principle cases.

[the_why_of_y]

I'd prefer if people forget about BSD/MIT and use ALv2 instead, for the patent clauses.

With the following preferred licenses you'd get explicit patent clauses, in ascending order of copyleft-ness:

ALv2 MPLv2 LGPLv3 GPLv3 AGPLv3

Perhaps the Eclipse Public License would also be an alternative at the same level as MPLv2 but I'm not familiar with it.

[dredmorbius]

Fair point.

ALv2 == Apache License, v2.

[ArtB]

Don't forget the AGPL.

[reitanqild]

GPL is just a subset of AGPL, isn't it?