It has applications in health care, pharmaceuticals, facial recognition, economics/related areas, and of course, much much more. Previously, MeFi discussed controversial homeland security applications, and the nexus between social networking and mobile devices that further contributes to the pool. With plenty to dig into, let's talk Data Mining in more detail. [more inside]
It has applications in Economics, Biology, Pharmaceuticals, and is rooted in State Space Modeling, which with Kalman Filtering (paper, breakdown [warning: long]) was used in the Apollo program. Dynamic Linear Models are gaining in popularity. There exists an R package, and both a short doc and a really great (read: worth buying) book (sorry, not a download, but here's chapter 2) by Giovanni Petris, Sonia Petrone, and Patrizia Campagnoli with its own little website.