A few years ago I began to collect graffiti stickers from the streets of San Francisco while I was walking in the city.  What began on a whim, has now become a bit of an obsession.  I now actively search them out, seeking to find the newest, coolest, and most creative in their expression, whetner hand made or machine printed.  There are a few corporate logos or commercially made stickers in here also, though I try not to collect them too much.  I began the SFGraffitiBlog on Tumblr last December as a way to share the collection with the wider world, since most people would never see the tags on the street.  The blog is in approximate chronological order, with the newest entries at the top.  I do not know who made most of them. If you do know, please feel free to leave their tagger name or handle in the comments section under the tag.