Open-source licensing: Your mileage may vary

Over the past 10 years that I've been involved in open source, one thing has become strikingly clear to me: there are no real predictors of open-source success. There are, of course, general principles that contribute to the creation of successful open-source projects, but serendipitous "right project, right time" circumstances often matter most.

I was therefore intrigued to read two articles that crystallized my own thinking around critical components of successful open-source projects.

The first is from BusinessWeek and details the mechanics of Mozilla's Firefox community. Mike Beltzner, Mozilla's director of Firefox, reveals that while 40 percent of Firefox is contributed by outside developers, what and where they contribute may not be what many would expect:

There's structure in (how Firefox is developed). But at the same time you allow people to innovate and to explore and (give them) the freedom to do what they want along those edges--that's where innovation tends to happen in startling and unexpected ways (emphasis mine).

This may be easier for the Mozilla Foundation, given its nonprofit status, as you'd expect developers to more willingly build around a product if they trust the foundation (pun intended) upon which they're building.

But the general principle holds: most open-source development and, for that matter, most development around proprietary software, happens at the edges. Whether it's Microsoft Windows or Mozilla's Firefox, developers generally don't touch the core: they create add-ons, complementary products, and so forth.

So, principle No. 1: Open-source projects that create a strong, valuable, easily extensible core that developers have the ability to build upon, as well as the pecuniary or reputational interest in extending, are more likely to succeed. No one works for "free."

The second principle is related to the first, and deals with ownership of add-ons. While some people are motivated by peace, love, and open source, others (rightly, in my view) see open source as a means to an end, and not the end itself.

As such, the license used for an open-source project matters a great deal. I've long been a proponent of the GNU General Public License (GPL) because it enables vendors to bless customers (free code!) while cursing competitors (we just open-sourced your entire value proposition and you won't dare touch our code!).

But lately I've been seeing the role Apache-style licensing can play in fostering vibrant open-source communities. Daniel Jalkut, founder of Red Sweater Software, describes this well:

As the developer evaluates communities to participate in, they must evaluate the legal impact such participation will have on their own project. The closed-source communities are, by definition, uninviting to outsiders. GPL communities are open and embracing of other GPL developers, but generally off-putting to liberal-license and closed-license developers. Only the liberal-license communities are attractive to developers from all three camps.

It's your party, and you're entitled to write the guest list. But take a look around the room: not as many folks as you'd hoped for? Liberally licensed projects are booming. Speaking for myself, a developer who has been to all the parties, I'm much more likely to pass through the door that doesn't read "GPL Only."

If you want maximum participation whatever the cost, Apache/BSD is probably the right way to go. Most companies and project owners, however, have to make a living, so it's reasonable that they measure the costs of going Apache, which likely means they'll trade a liberal license to some of their code for a proprietary license of the rest of their code.

IBM is an example of this strategy on a big scale, but so are Day Software, Microsoft, SpringSource, and others.

Principle No. 2, broadly stated, is this: Your odds of encouraging adoption of your product go up if you use a liberal license like Apache, but your ability to directly monetize Apache-licensed code vaporizes.

This isn't a bad thing. It just means you have to separate community creation from customer creation, as Funambol's Fabrizio Capobianco has stated. The two aren't necessarily the same, and are sometimes inimical to each other.

As noted above, however, you don't have to license your software as open source to encourage community around it. Microsoft, with its vibrant partner ecosystem, demonstrates this, as does Apple with its amazing iPhone ecosystem.

Developers will flock to the platforms that offer them the most return, whether financial or in reputation (which eventually translates into money). Liberally licensing of your code might tip the scales in your favor if you lack the largess of Apple or Microsoft. But no guarantees.

Follow me on Twitter @mjasay.