ok, since i hardly ever post on topic, let me try it out.
Critical Mass is a good idea, but it is executed poorly.
just for background (i know most people know this), the term Critical Mass came from a westerner who made some observations about bicycling in China, where the rule of the road is the bigger the vehicle, the more right-of-way. well, bicyclists that need to take a left at an intersection find it almost impossible to cross the other lane of traffic if they are alone. they wait there until they accumulate a bunch of bicyclists all wanting to turn left. at some point, the group reaches critical mass, where the group becomes large enough to have right-of-way to make the left turn. the oncoming traffic yields to the "larger" vehicle.
i love the idea of a bunch of cyclists being "one" vehicle. supposedly, some of the earlier tenets of CM was that if the head of the mass goes through a green light, then the rest of the mass follows (even after the light turns red). this is legal because it's all "one" vehicle.
so, problem #1 for me with SF CM, is that the pack does not stay together well enough. in my mind, it should be a cohesive and dense pack.
problem #2 - and this happens all the time - the mass goes through Union Sqaure. great, the mass gets exposure, you get to see some babes shopping, you're in the middle of the city. but then, for some reason, the riders in front decide to go all the way around the square. so, the head meets up with the middle of the pack, and then there's no head, no tail, and it's just a big merry-go-round. that bugs the **** out of me.
and then there's the times when the pack heads through a tunnel, and after they get through, they promptly jump the curb and go back through the other side. just annoys me.
i envision CM as this ephemeral entity that snakes through the city. one second it's there, the next second it's not. instead it ties up the broadway tunnel for an hour for no reason.
so, have fun if you go! great weather for riding today.