Earlier I noted the growing security crackdown in Egypt; Marc Lynch has also written about the dangers that the disorders could be very bad news for the Egyptian revolution. As part of the current security crackdown, the Military Council has said that the Emergency Law, which has also been amended, will be extended to at least mid-2012.
Of course if everything goes according to the alleged schedule, a new Parliament and President should be in place before then, Earlier pledges to end the Emergency Law as soon as possible are now off the table, and it doesn't sound as if the Supreme Council of the Armed Forces plans to just go away after elections.
And of course, that raises the question of what exactly is going to happen with the elections. Tunisia is on track to begin its campaign for a constituent assembly, and Egypt still seems to be thinking about what happens next.
Most of the agenda of the Friday demonstrations had to do with getting the process back on track, but the violence against the Israeli Embassy has sidetracked that and discredited many of the demonstrators. (An attempt was also made to storm the Saudi Embassy, which failed and thus got little attention.) It could prove to be a rather unfortunate tipping point.
To end on a positive note, however, I'd refer you to this post of Sandmonkey's; it was posted before Friday's violence, but its message is an encouraging one: the real achievement of the revolution is the realization that the people can bring about change. That won't go away even if there are setbacks on the road.