data on license usage [was Re: MPL 2 section 11]

[Simon Phipps]

On Nov 23, 2010, at 16:35, Luis Villa wrote:

> [Slightly OT, apologies]
> 
> On Tue, Nov 23, 2010 at 8:17 AM, Schmitz, Patrice-Emmanuel
> <patrice-emmanuel.schmitz at be.unisys.com> wrote:
>>> Well, that's why permissive licenses exist, but the MPL is not one
>>> of them.
>> 
>> Exactly, John! This is the reason why interoperability must be implemented between the most used copyleft licenses...
> 
> What do folks here find to be the best/most reliable list of widely
> used licenses? I've looked for such data myself, but I've not found
> much I'm happy with, especially when you're looking for data on
> licenses which are not hugely popular, or when you're looking for
> license use on non-Linux projects (since most of the highest-quality
> data is derived from analysis of Debian and Fedora.)

As you indicate it's a really hard question, as it depends on the metric you choose to use for "widely used". Within any given community, certain licenses are highly important and yet the same licence may be disregarded in other communities. Sheer volume of files licensed isn't a very useful guide as it gives no indication of the needs for combination that are arising at the boundaries between communities. 

The company where I work engages in multiple communities where the license in use is CDDL for historic reasons. Since we're not (and never will be) the copyright holder, we will need to live with that for ever. So for us, the communities we participate in and the users of the software we work with, CDDL is by far the most important licence, and we would very much like to be in a position to freely combine code with MPL 2 code in the future. However, CDDL is unlikely to be high on any lists of "widely used licences" despite its high importance to these communities. 

I'd thus suggest being liberal with your list of secondary licences. As a minimum, I suggest the list on http://opensource.org/proliferation-report of Licenses that are popular and widely used or with strong communities (with the addition of GPLv3 et al and EUPL which have arisen since the report) be accommodated.

S.