License compatibility of MS-PL and MS-CL (Was: (RE: Groklaw's OSI item (was: When will CPAL actually be _used_?))

[Rick Moen]

I wrote (replying to Michael Bernstein):

> I'm perfectly glad to agree to disagree -- holding, as I do, that going
> beyond "Derivatives must be compatible with this licence" to
> "Derivatives must be under exactly this licence" is merely pigheaded and
> self-defeating but not non-free / proprietary.
[...]
> I see OSI's licence-certification mission as identifying licences that
> can delimit software commonses, within which recipients are guaranteed 
> rights to use for any purpose without fee, redistribute, and create and
> distribute derivative works that perpetuate the same permissions.
> However, it isn't certifying those as good licences, let alone vetting
> them as being likely to create a _healthy_ or lasting or reasonable
> commons.

As an afterthought:  If one stipulates that MS-PL and MS-CL prohibit
creation/distribution of derivatives involving any other licence terms
than their own -- which I'll buy, based on recent discussion -- it is
nonetheless _not_ true that each delimits a commons cut off from the
rest of open source.

Direct code borrowing within derivative works is hardly the only way to
use codebases in combination.  _Many_ other ways to create software
composites exist:  library calls without derivative work usage within
the meaning of copyright law, xmlrpc, object brokering, and a vast
number of other types of interprogram communication.