The attackers in plainclothes were members of the security forces. I've witnessed protests like this before in Jordan. Similar protests have occurred in Egypt and almost everywhere in this region for years. They always end "quietly", with hundreds arrested, torture, indefinate imprisonment and, for some, death.
It seems that these protests are being organized mainly by leftist and liberal activists (although many Moslems are are also participating). Islamic organizations have far deeper and wider grass-roots support in Egypt and the entire region, and therefore are a far greater threat to dictators, and their colonialist sponsors.
In the last deacde, its seems that the US has been encouraging its client states more restraint when faced with critisism and protest. (Although, the US itself is becoming more aggressive and intolerant since 11/9) The idea is to prevent people from moving away from co-opted and controlled movements (ie. Moslem Brotherhood) and moving towards more independent, underground, and less controllable political movements.
Also the international media is reporting the protests. Possibly because of these factors the government is not cracking down on the protests as severly as they usually do.
Throughout the Arab world there are sentiments common to almost all people. Political, economic, and military independence, and unity of entire region, which requires freedom of expression, improving education, and opposing and protecting the region from western interference - where removing Zionism from Palestine is the most recognizable call. (All noble goals towards which I hope all conscientious people can unite in support.)
The US, and Israel, would never allow this of course.
The only real reforms the US will allow are some beaurocratic and cosmetic changes (away from (UK-style) monarchy towards (US-style) "democracy". The people themselves, of course, will not be allowed any role or real options, other than to accept what ever leaders are chosen for them.
As for Kifaya, I expect this movement will be co-opted, by encouraging "moderate" reformers, and the government cracking down on the less co-operative elements who will be accused of violence or encouraging it, framed and labeled "terrorists". Protest will die out again for a while, as the world looks away.
[ 31 July 2005: Message edited by: salaam ]