I saw on Grant's blog that he is working on a new project, Mahout.
The goal of Apache Mahout is to enable scalable machine learning algorithms on large clusters. It builds on the algorithms outlined in Map-Reduce for Machine Learning on Multicore. It looks like the project is just getting off the ground. It's only been active since January.
Mahout just announced that Sean Owen's Taste recommender system will be added absorbed into the project.
You can also read Jeff Eastman's blog, one of the committers on Mahout.