We are preparing a new release of MOA 13.08.
The new release of MOA will contain the FIMT-DD regression tree, the Adaptive Model Rules, a recommender system based in BRISMFPredictor, and some more features in clustering and a new outlier detection tab.
You will find the source code at the repository:
https://code.google.com/p/moa/
Cheers,
The MOA Team