It's the return of the notorious, Possibly NSFW, although it is on the sidewalk
this is in the rear doorway of Marinello's School of Beauty, 1035 market (Stevenson alley near 6th Street), Sunday April 4, 2011.. Previous sightings of this person here, and here
update April 17, 2012, video was banned on Youtube recently (yes it took an entire year.) Here it is re-upped on Live Leak (same thing happened with Crackheads of the Day #29). Coincidence or not, 1035 Market street houses the SF Aids Foundation and the Stonewall Project (the front page being a text version of this video)
Google is reporting suspicious activity regarding malicious software at www.beyondchron.org, a division of Tenderloin Housing Clinic and headed by Randy Shaw
below are a couple of screen shots. They are only photos of the report and not the attack page itself. Clicking through only takes you to Flickr