<< what's the point of running dc on your comp? >>
To waste electricity.
As far as I know, not a single distributed computing application has ever come up with any useful information, despite the billions of hours of CPU time.
RC5 - Using millions of computers to try and prove that you can knock down a locked door with a battering ram
SETI - Using millions of computers to look for "something" who or what that is or whether it even exists is unknown. They haven't found it yet.... wonder why.
At least the cancer one has a useful goal, but I haven't heard of anyone progessing towards a cure based on the DC application. I think a cure for cancer will require a lot more input from intelligent doctors than from computers gonig through every possible combination of some algorithm.