I completely agree with the subject-line - my own favorite approach is
"contracts", like the one between --I think it was PlanetMath, but it
could have been another "host" organization-- and Springer to build
statprob.com, which is a Noösphere-based site about stats that is
still online and at least somewhat active.
I think
montyprogram.com has a particularly nice model
(
http://montyprogram.com/commercial/ -
http://montyprogram.com/hacking-business-model/), and I was also
favorably impressed with
freecode.no when I visited (though they've
recently been bought, and I don't know how that impacts the way they
do business). Basically they provided free software services for
enterprise.
In the big picture I think there's an important difference between
"premium users" -- who get special treatment within a running instance
of a program -- and "premium licenses" (which typically add non-FAIF
features to FAIF programs, for a price). Access to resource-intensive
services should indeed come at a premium, but my own idealistic view
is that all *code* should still be released FAIF.
I've previously shared by thoughts about building a free technology
guild (
http://campus.ftacademy.org/wiki/index.php/Free_Technology_Guild)
-- I think this would be a very good use-case for Planetary and some
related semantic services, with I think more potential to turn a cash
profit than the pure math use cases.