This is only a teaser for what is to come. As more and more people use broadband (and more precisely, Peer to Peer), the ISPs are going to have to limit usage.
I admit, they've done it a bit sneakily. NTL for one, couldn't bring in a real cap to current users, as it wasn't in the original contract. However, now they are enhancing our speeds in 2 months time, its a new contract, and thus they can include this cap.
Its necessary, but bloody annoying.