This type of processor implements nondeterministic finite state machines². Effectively it allows you to perform regular expression matching, very fast and on large data sets. They implemented this in a very clever way exploiting the fact that DRAM access is extremely parallel by nature. It is useful to solve data mining problems, such as those arising in bioinformatics.

It is quite likely that there are also certain government agencies among the early customers...

²http://en.wikipedia.org/wiki/Nondeterministic_finite_automat...