Progressive licensing is discussed at http://softdevelcoop.org. The gist of progressive licensing is as follows. The work is open, unobfuscated, derivatives may be created and distributed. The owners may retain the right to charge royalties for economic use of the work.
As far as I can tell, ProgressiveLicenses would not be approved by either the FreeSoftwareFoundation nor the OpenSourceInitiative? since they exclude a category of use of the licensed work, namely "economic use". On the other hand, they look like a fairly well-considered attempt to reconcile IntellectualProperty-as-capital with BazaarStyle development practices.
Looks like it would probably pair well with TransCopyright or an (advisory, non-enforcing) DigitalRightsManagement protocol. -- JeffreyHantin