Jack Hughes has a great post on The Tech Teapot today. He has been examining the effects of an “open core” licensing model on open source communities, and he hypothesized a “functionality ceiling” in such projects as the feature needs of the pay or commercial version outweigh those of the free or community edition.

Using Ohloh he was able to examine graphs of the code for two well-known open core projects. Both of them show a large plateau, seeming to demonstrate his point.

So I decided to look at the OpenNMS graph. It’s considerably different.

This is pretty cool. You can see a bump when I took over the project in 2002, but due to my limited Java skills it doesn’t grow much until 2004 when Matt Brozowski joined the project. After that the growth is pretty phenomenal. We do have a slight plateau as we are preparing for our next stable release, but nothing like the 18+ month long ones for the other projects, and the size of our code base is much, much larger.

Great idea, Jack.