Ah, fair enough. I had assumed it was to do with having a few block set in stone and propagated around the network, but it sounds like its more entwined with the 51% question and that sort of stuff...
Max is correct, but the new idea is basically to incorporate all the computation that goes into side branches that end up abandoned, so you get equivalent security in a much shorter time.
I think it's one reason we won't really see a huge proliferation of alt coins (even here you regularly have dreamers posting 'there should be cryptocoin for that').
