These are not just computers. They are committees, or you might say mobs, of tied-together computers. Some of them have over 200,000 individual processors.
I think most of the individual processors are all doing the same thing.
No--mobs have no leader. Supercomputer clusters all have a leader, an organizer. They are more of a republic. :)
The folding@home project promotes that it has over 2 exaflops of processing power.
Pretty amazing considering where we were just a couple of years ago.