One piece of interesting news I've just read in here:

http://blog.wired.com/27bstroke6/2007/10/att-invents-pro.html

An AT&T research paper published in 2001 and unearthed today by Andrew Appel at Freedom to Tinker shows how the phone company uses Hancock-coded software to crunch through tens of millions of long distance phone records a night to draw up what AT&T calls "communities of interest" -- i.e., calling circles that show who is talking to whom.

...

With Hancock, "analysts could store sufficiently precise information to enable new applications previously thought to be infeasible," the program authors wrote. AT&T uses Hancock code to sift 9 GB of telephone traffic data a night, according to the paper.

The good news for budding data miners is that Hancock's source code and binaries (now up to version 2.0) are available free to noncommercial users from an AT&T Research website.