The site is powered by OSQA (http://osqa.net), a Django/Python Q&A platform. The site is a fork of CNPROG, which was designed to mimic StackExchange.
OSQA is supported by DZone, and the pace of development has been rapid. The core developers have stated on many occasions that they are moving in independent direction from StackExchange.
In particular, because the site is open-source, I can experiment with adding NLP to it. I can improve the Related Questions, I can automatically infer tags, and I can implement techniques for helping you organize and navigate information.
As Chris Manning (Stanford NLP professor) says, Area 51 hasn't gotten any buy-in from the academic community. I have focused on getting academia to be the immediate core of the community, so that the quality of Q+A is high. I am able to do this because of my academic connections.
The last thing we need is NLP and ML people communicating less. That's why my site encompasses all of these proposals, as well as adjacent fields. As we've learned from StackOverflow, having one site for a broad topic leads to cross-polination of ideas between groups who don't normally communicate.
Most importantly, OSQA (which powers my site) is an open platform, built on Django+Python. That comes with all the benefits of open software. In particular, because the site is open-source, I can experiment with adding NLP to it. I can improve the Related Questions, I can automatically infer tags, and I can implement techniques for helping you organize and navigate information.