Reading the G20 coverage. Looks like the black bloc is up to their usual thing, smashing windows in Toronto. Looks like the traditional response is about to kick in, too, as the police start firing off the tear gas.
Expect escalation. Twitterers appear to be saying that the black bloc are only about 100 out of the thousands of protesters. But once the relatively peaceful majority starts smelling the tear gas, at least some will decide to join the black-clad anarchists in the violence. This is almost certainly only going to get worse, though Toronto's poor weather this weekend may help diminish things.
What I'm really concerned about is what happens tonight. There is supposed to be some kind of "all night unpermitted dance party". It's not supposed to be a protest, and certainly not a violent protest. But if the police try to clear these guys off the streets, it could get even uglier than what the world is seeing right now.