The estimates vary but even NPR was saying "hundreds of thousands" of people demonstrated in Syria yesterday.
Today the governor of Hama - one of the protester's main targets (the other is Assad) was fired.
I'm surprised the Intrade market for Assad has not increased - currently trading at 25% chance of leaving which seems low. One of my theories is that any country in this region that has a large enough protest is guaranteed to change its government. However, so far this theory has not been doing too well (Bahrain has been an exception - though give it a year and see what has happened).
The government's response to the Syrian protests has been very violent, so I would not be surprised if the violence were to increase in response to the larger protests (like what Bahrain did). Perhaps they might try to impose martial law (tanks in the streets everywhere) - one that is stricter than the current situation (as I've heard they are already using the military). However, unlike Bahrain, they have to rely on their own military. And unlike Libya, they might not have large amounts of money to throw around to pay people to do the dirty work. So a violent crackdown is more likely to split the army on the side of the people.