The current NP looks mysteriously similar to tdeb. I mean, there's the new blog stuff, and maybe the store is finally working. It almost feels like new versions keep surfacing with little change. I think the next NP (there undoubtedly will be another) should have all the new features finished.
There is no shared code between TDEB an NP7. Some of the features of TDEB might've been a good idea and gotten incorporated into NP7 but I don't know. In general the feature set of NP has been largely the same post-NP4 (I think, any old-timers want to verify?). What has been going on is a lot of refinement at the implementation level and how things work / site direction.
With NP7 there are, however, two cool new features (that are finished).
1. Blogs -- these were incorporated because people have long been wanting a good way to help contribute. These blog posts basically a few clicks away from being promoted to the front page -- if we notice something that stands or if you write something you feel is of high quality bring it to our attention.
2. Knowledge Base -- There is a _lot_ of intelligence distributed among NP users. This is where you can go to ask questions and leverage that intellect. Right now the strongest sections of NP Knowledge Base are technical and math, we'd love you to sign up and ask/answer questions. It's actually pretty rewarding =)
There is quite a bit more with NP7 that we'd like to roll out but there are only so many hours in the day.