[tlug] GPL vs. paid version and ethics

["Stephen J. Turnbull" <stephen@example.com>]

Darren Cook writes:
 > Nowadays commercial software and open source co-exist. In particular a
 > common model is for a GPL version and then a paid version with more
 > features. E.g.
 >   http://www.infobright.org/Learn-More/ICE_IEE_Comparison/
 > 
 > In that particular case I was curious about "Multi-core query
 > execution". I wondered what would happen if I were to add that feature
 > (*) to the GPL version.
 > 
 > Legally I can do it.

*That* is a risky bet unless you can afford a patent search.

 > If they host the source code, they could refuse to accept the
 > patch, so I'd have to branch, and then there are two versions going
 > forward.

That would be dumb on their part, but it could happen.

Why dumb?  (1) They look like they're deliberately dumbing down the
free product, which is bad PR.  (2) If your patch is competitive with
theirs, they learn something.  (3) If it's different and not patent-
encumbered, it may represent insurance against a submarine patent (if
you're willing to give them a commercial license for your code).  (4)
If your code is not competitive, that's maybe the best of all possible
worlds: they look good and the people who really want performance buy
the commercial product anyway.  (5) It's a rare feature that induces a
huge number of people to buy a software product.  People buy products
for support and other reasons.

So the net result is that if your patch is even marginally usable, the
GPL version becomes an even more attractive introduction to their
product line.

 > But I also wondered about the ethics. If I added that feature I cut into
 > their sales. Financing for the product goes down. Product quality goes
 > down. Well, in, one scenario.

Unlikely scenario, though.  Of course it's possible that they
seriously misunderstand the dynamics of dual licensing, but the fact
that they do it at all suggests they have some clue.

 > *: An academic question; I am aware of how much work that could be,
 > and I have more interesting things to do.

And almost surely you'd stop at proof of concept, unless you were
getting paid for the work.  It's unlikely you'd achieve commercial
quality of the whole product.