StackOverflow is CC-SA 2.5 licensed. The "derivative" site is also CC-SA 2.5 licensed. They both have clearly different audiences. I don't see a problem.
* 4 prominent attributions: SO attributions on his blog, the google code main page, CC license on the new production site, and in the code itself!!!
* apache open source license
Maybe he is not in full compliance yet, but this is one hell of a good start and demonstrates good faith.
I think the proper way of attribution would be a link (or message) in the footer or, at the very least, on the about page. Maybe I'm being pedantic, but if I need to search for the attribution by going to the developers blog or viewing the source code, I don't think that's enough.
This is beside the point, because I agree that the other forms /are/ attribution, but I don't consider the creative commons link a form of attribution at all.