Off-topic, but since you mentioned it: do you know if HN user potatolicious has seen your SF poo blog? He's commented on that phenomenon many times here and I'm sure he'd appreciate your Tumblr!
Hmm, I don't think so, I was only able to get 3 different pictures because I ended up moving. Here it is, for the record (warning: poo) http://sfdisgusting.tumblr.com/
Sure is a lot of poo on the sidewalks and in public areas in SF. I don't think I've ever seen someone just pull their pants down and push out a brownie in the middle of the sidewalk anywhere else but there.
Yup. When my mom came to visit me, she came back to my apartment one night and said, "you'll never believe what I just saw." I already knew what she was going to say, it was that she saw a homeless guy pull his pants down in broad daylight next to a trash can to relieve himself.