Hi!
And is also infeasible. For a web service. GPL is effectively weak copyleft already; I think that's quite weak enough. (As I noted, there is no actual evidence that permissive licenses secure more
This is very plausible, as the decision to contribute is rarely driven by the license as a primary factor - you don't say "here's random GPL-licensed project, I don't know anything about its domain, language, goals, community, status or needs, but I feel compelled to contribute because it's GPL!" - or at least, most people won't say that. As long as the license is not completely un-acceptable, I would assume other factors would dominate such decision. However, I know cases where I personally had to write code or otherwise work around GPL libraries because of license incompatibility with other open-source projects. That, of course, can be also counted as "more contributions" but I don't think that's what you meant :)
contributions than copyleft, and some evidence the other way; despite
Out of curiosity, what evidence you mean?
fans of permissive licenses repeating the claims ad nauseam over the last fifteen years, they're notably short on examples.)
You must already know examples of successful projects under permissive licenses. So you probably seeking the examples of why permissive license solicits _more_ contributions that if the same project was under GPL. Such example would require a rather rare occurrence of a project changing the license while at mature stage and measuring the contributions before and after the license change, otherwise we'd be comparing apples to oranges. My personal opinion is, as I described above, that license doesn't matter too much provided it's not unacceptably restrictive. Thus, for me looking for such examples would be a waste of time :)