When websites are more like apps, we need to be able to grant or deny permissions to them like we do any other software. A firewall or whitelist that allows or denies code full permissions based on its origin is too coarse, and most people aren't even doing that much with their desktops, let alone their browsers. Browser security is probably the next big battleground.
Mokalus of Borg
PS - Actually, it's probably the big current battleground.
PPS - It is, after all, the biggest sector of computer use right now.