BlogBridge open source license

I've done a little research about what the Open Source really means, legally, when it comes to BlogBridge. I wrote about this question a few months ago, and now, having consulted with people who know, here's an update.

First of all, start with the goals.

• BlogBridge should be available, in source code form and executable form to everyone who wants to look at it and use it. It should be a bona fida open source project.
  Reasoning : We will be able to recruit others to help us build it; It is a significant differentiator among the other blog readers out there; And we can legitimately use services such as Source Forge to manage the project and its source code.
• If a commercial entity wants to use the code to build a commercial business, we would like them to have to come to us for permission.
  Reasoning : Obviously, we aren't making any money on this; if someone else wants to, it would be nice if we were involved.

As it turns out, this is not an unusual set of objectives, and it is pretty straightforward to achieve.

As of BlogBridge 0.5.4, the product will be licensed under the GPL (rather than the LGPL which is what we had before.)

The effect of this is that the first objective above is fully achieved implicitly. The second objective is achieved, indirectly:

Because the GPL is quite strict in its requirements of releasing any modifications, enhancements, etc also under the GPL, it makes the source code as it stands unsuitable for a commercial purpose. The obligations attached to modifying the source would really discourage anyone from building a business around it.

(You might wonder, once you've released something as Open Source, can you decide to change the license? Isn't that prohibited? It turns out that it's perfectly alright.)

The code as it stands therefore is incompatible with a commercial project. If we decide that we want to embark on, or give someone else the ability to embark on a commercial project, what do we do?

We release a copy of the source code under a different, commerical license. This copy forms the basis of the commerical project. It's called "dual licensing " and it's a well understood and accepted model.