Skirmish between driver, Critical Mass participants triggers another round of debate about monthly ride - San Francisco's often-heated dispute between bicyclists and drivers flared anew Wednesday as news of a confrontation between a minivan driver and Critical Mass riders sparked outrage. In blogs, as well as on the streets of San Francisco, Critical Mass seemed to turn everyone into a critic. An SFGate.com blog received hundreds of comments, many vitriolic, about Critical Mass. Mayor Gavin Newsom denounced the aggressive attitude of some cyclists, and police officials said they wanted to meet with biking activists about the monthly ride. The incident...