Vanilla is licensed under GPL v2! Why NOT GPL v3?
Vanilla license => http://vanillaforums.org/docs/license
Why NOT gpl3? Tivo is available on gpl2 but "GPL v3" closed doors for tivo!
GPL2 vs GPL3 => See this table
So, why vanilla developers team hasn't upgrated the license to version 3.0?
Maybe related discussions: http://vanillaforums.org/discussions/tagged/license/p1