It may be that future ages will decide that the most important invention of this millenium is the GPL, if it turns out to be half as productive as the printing press was (and it might). Then again, they may decide the plastic bag was a more important advance, or possibly resevoir tips for condoms. But inventions can sometimes be improved, as that last example shows, and I'd like to make a modest suggestion for a variation of the BSD license and GPL license, that might be quite productive.
As is described here at everthing2, the BSD license endorses forking, even with additional copyright limits. This includes forks that are or become GPL, and someone should do just that. This might add a snowball effect to a very secure and stable system.
More particularly, a hybrid BSD/GPL license could be created which allowed modification with a delayed release (under software escrow only) of the new code, of, say, two or four years - enough time to earn some money, and then the code becomes part of the general wealth of humanity. Additionally, the modified product could be held private for that period, and sold, rather than being freely available for copying.
Arguably, this is how the software patent and copyright system ought to work anyway - seventeen years plus extensions for a patent, or a lifetime plus fifty years for a copyright to expire just don't jibe well with cyber time-scales. Two-year or four-years might be more than long enough to allow a company to make enough profit to make it worthwhile for them to fund substantial improvements to a code base, yet allow the freely available product to swiftly gain usability. It might restore the balance of private incentive and public good which the patent and copyright system was founded to create, in order to encourage innovation.
You can start this today because nobody's permission is needed to create a BSD/GPL hybid license fork of anything covered by BSD. Anyone - and or any company - can start the process.
Now I don't mean to argue that BSD, GPL, or private property for that matter are inadequate, or not useful - I actually think each of these has some place, and that they'll all continue to exist, and be useful. But I suspect that just as the slight copyright restrictions added to the BSD (or outright renunciation of copyright) which create the GPL, give great power to that license, and additional complication, so too, allowing a time-limited amount of profit might power up (a varient of) the BSD license and put additional momentum behind open source in the commercial marketplace. And that would be a good thing.