Think out a strategy for getting graffitweeters.
The most basic strategy is to pay for them.
It is not going to happen by itself, I have been doing this long enough, and although there might be a slight uptick in the number of people using twitter to 311, it is mostly about muni, and almost just me on graffiti.
I did an analysis for Dolores Park and Mission District.
Assuming that people are just going about their normal lifes, and graffitweeting when they see a graffiti that bothers them, to clean up Dolores Park, it would need about 4-7, and 40 to 80 for the Mission District.
Dog people at Dolores Park are good candidate. They are at the park every day. Further thought.