The fear of “GPL contamination” is what the business of dual licensing GPL code is based on; you use the GPL version as a ‘try before you buy’ marketing tactic and put the software freedom community to use as a marketing team. The stronger the copyleft (ie, Affero GPLv3 is the strongest) then the higher the conversion rate on the non-GPL license will be.

Given this post is now many months old, perhaps you could make a new post reporting how things have gone?

I think you should talk to the major functional software houses/groups (Galois, various banks, and Jane Street come to mind) and see if any of them want to publicly “sponsor” your development of Reactive, under the original BSD license.

Many of these shops are a) Trying to attract functional programmers and want the name recognition of sponsoring one of the coolest ideas out there b) Wanting your expertise if they use the product (I can imagine Reactive would be quite useful to a bank) c) Open to the bleeding-edge

Slapping their logo on the website, and getting consulting hours and gratitude from you accomplishes all of these things.

The above might sound facetious, but it is only half so. This is a growth sector at the moment. Think outside the thunk.

The objection raised by Anon (“Please not the GPL”) were already addressed in Ryan’s comment: if you don’t like the GPL you need to cut a separate deal, probably involving money flowing to Conal. That is the point!

But then, if you interpret consulting as mostly training and advice, you might be able to earn bucks by explaining people how to design — in general or for a specific application — programs without falling back into pre-FRP patterns. Add a little viral marketing via a google techtalk and…

That almost sounds like a defintion of the word enterprise in the term “enterprise software” – free or non-free.

I’m not recommending you go the route at all though. Personal integrity matters and ultimately will probably prove to be good business.

I think you need to consider a broader strategy than just licensing. The majority of open source developers I’ve know who’ve been at it seriously for more than 5 years now earn a professional living from activities related to it. [...]

Joseph added:

Keep things free and unencumbered for the community, and offer consulting services and a commercial license for enterprises which need support.

Thanks for bringing in this angle. I’m puzzling over how it might apply to my work.

What I’m most dedicated to in my work at is creating software that is simple to reason about (understand precisely) and to use. It’s a tremendous effort, and it’s my mission.

In order for free software to generate consulting & support business, I imagine the software has to be tricky/complicated to use. Is that so?

I also strongly agree with Robert Burrell Donkin. I think that you can maximize your personal value by keeping the license open and fostering a growing community. JBoss and MySQL are great examples of very successful outcomes from this approach. Keep things free and unencumbered for the community, and offer consulting services and a commercial license for enterprises which need support.

Nokia bought Trolltech for Qtopia rather Qt – Qt recently went LGPL. Qt revenues funded the initial growth of Trolltech though.

I’m personally very uncomfortable about this part:

You must purchase a Qt Commercial License from Qt Software or from one of its authorized resellers before you start developing commercial software. The Commercial license does not allow the incorporation of code developed with the Open Source Edition of Qt into a commercial product.

I think that statement is completely bogus, and not even good business. It is not part of the license – just commentary on the license. What would Trolltech have done if a potential customer had been openly evaluating Qt for closed source use under the GPL? (That would be perfectly legal, even for companies the GPL only starts to matter when one redistribute the GPL’d code.) The potential customer then decides they like Qt and goes to Trolltech sales and says that they would like to buy 50 commercial seats. Rank the following from most likely to least likely:

1. (1) Trolltech sues the potential customer.
2. (2) Trolltech refuses the business, but does not sue.
3. (3) Trolltech takes the money.

My answer would be (3), (2), (1).

It is arguable that Qt would have been more successful without the clause scaring potential customers away.

For the consultancy model to work, Reactive would be very powerful (sounds like it is) so that it was attractive, but an absolute dog to integrate (sounds like it is not) so that lots of expensive consultancy would be required. Think Enterprise Java for example – Marc Fleury et al’s JBoss was a good service business on a GPL core, which they sold to Red Hat.

One other point is that you can’t unlicense code that you have already released, so if you were to make the license of future versions of Reactive more restrictive than BSD3, you may have to compete against forks of the current Reactive BSD3 code base. That would be either other companies competing against you, or potential customers avoiding your license fees.

Do you have any examples of code/projects that have successfully developed along the lines that you are thinking?

Hi LA. I’m way too new to even thinking about licensing to have such examples. Perhaps Qt is one example, though I have no idea how successful Qt is, technically or commercially. It seems to be the canonical multiple-license poster child. There are some license-related links on the Qt licensing page. I’m personally very uncomfortable about this part:

You must purchase a Qt Commercial License from Qt Software or from one of its authorized resellers before you start developing commercial software. The Commercial license does not allow the incorporation of code developed with the Open Source Edition of Qt into a commercial product.

I’d love to hear answers to this question from other people. What success stories do you know of for software that is free for non-commercial use and available for non-free commercial licensing.