[genwin]

From GPLV3: "One of the fundamental requirements of the GPL is that when you distribute object code to users, you must also provide them with a way to get the source."

Presumably MSNBC didn't distribute object code to users, in which case they have no obligation to open-source any derivative work.

[jlev]

And that's why you should use the Affero GPL for web services. http://www.gnu.org/licenses/agpl-3.0.html

MSNBC really screwed the pooch on this one, from their initial "open source" via zipfile, to the zero-day shutdown. Not what the Knight Foundation intended to fund with their open source requirements.

[cedrichurst]

Per another thread of discussion, apparently the rules of the GPL do not apply to the licensor, only the licensee. If MSNBC accepted OSS community contributions to the Everyblock codebase, they might be in violation. But if it was a one-way offering, they can apparently still retain full rights. I imagine the initial Mozilla-Knight foundation grant makes this a bit more complex, but IANAL.

[jlgaddis]

The key is distribution.

Anyone can take a piece of GPL'd software and modify it as much as they'd like for their own use. There is absolutely no requirement to publish or "contribute back" those changes. (Think, for example, about Amazon customizing or modifying Xen for EC2. They do not have to publish their modified code or share it with "the community".)

If, however, you share binary/compiled/etc. forms of your modifications, you are then required to make the source code available.

[jlgaddis]

As a follow-up to myself, if you are the copyright holder you can do whatever you'd like with the code including, for example, dual licensing.

Many, many years ago (I'm not sure if this is still true (I doubt it)), MySQL was dual-licensed. It was free for personal use, for example, but if you wanted to 1) use it commercially or 2) run it on Windows, you had to pay.

Perl, AFAIK, is still dual-licensed under the GPL and the Artistic License.