For anyone interested, the Knight Foundation helped fund EveryBlock with a grant that required them to open source their code. http://code.google.com/p/ebcode/
The grant required that they open source it at the end of the grant period so I wouldn't be surprised if the source code was not current but for anyone who would like to keep it alive, this would give you a major head start.
The source was dumped with no version history once in 2009. So, yes, out of date.
That said, I know nothing of the conditions around this, what their plans were, and so on - so not judging. And a site like EveryBlock is less about source code and more about execution and moderation, which they did quite well for a time.
They own the copyright to the code: they can do what they want with it. The licence is only a restriction on what people who don't own it can do.
Also, the GPLv3 is not the same thing as the AGPL. Even if they didn't own the code, if it was only GPL then they could make changes without making those available since they were not distributing the software (assuming this was just a webapp). The AGPL closes that loophole.
Copyright licenses apply to third parties, not owners.
The GPLv3 compels entities other than the copyright holder to make available source code to those who receive non-source code versions of software, if they are actually distributing the software or "offer access" to the work (e.g.: as a Web app). The copyright holder him or herself, whether by authorship or assignment, has no such obligations. Third parties would, as would the project maintainer if that maintainer accepted third-party contributions without assignment.
If the Knight Foundation grant required continual availability in open source form, that would be a different contractual obligation under the grant.
Just because this code is released under GPLv3 it doesn't mean that the main codebase is GPLv3. They have complete ownership of their own code & can do as they will with it. The GPL only controls the rights of other people that want to use it.
I was on the site nearly every day and poured hours of my life writing community posts, updating information, etc. This may not mean much to people outside of Chicago, but stuff like the epic debate between Eddie Carazana and Jim DeRogatis on the future of the Congress Theater, gone forever?
The grant required that they open source it at the end of the grant period so I wouldn't be surprised if the source code was not current but for anyone who would like to keep it alive, this would give you a major head start.
Also, it appears someone already did something with the source @ http://openblockproject.org/