New prime number

The number (2^43112609)-1 is prime.

According to
http://www.ironictimes.com/0420-p2.html
the new prime number was found in Henry Paulson's bailout proposal. ;)

I used to have a program that ran in the background on my machine to look for prime numbers. If I had stayed with it, it might have been me that discovered this prime number. I would have had one more trivial fact to bore friends with at parties. I stopped the program when the computer became strapped for memory -- the program was small, but still took up some memory.

I also don't quite understand why we keep looking for new prime numbers, except for the fact that they are there.