Q&A sites.

Everybody knows MathOverflow by now but two new sites have been showing up on my radar screen lately (Thanks Aleks)

Statistical Analysisis a proposed Q&A site for statistics, data analysis, data mining and data visualization.

And there is a new site MetaOptimize that features Q&A's about::

A community of data geeks interested in machine learning, natural language processing, artificial intelligence, text analysis, information retrieval, search, data mining, statistical modeling, and data visualization, as well as adjacent topics.

The latest questions related to some of the issues discussed here on Nuit Blanche include:

• What is the best introductory text on Random Matrix Theory?
• When should you prefer GraphLab over MapReduce? And vice-versa?