Blockies allow camera phone users to post pictures on any public surface, using special stickers.
See something cool on the street? Take a picture and a Blockies sticker. Each sticker has a unique code on it, so any place you put the sticker gets tagged with that code. Whenever you send pictures to Blockies.com from your cameraphone, you put the code in a message to email@example.com, and they link your picture to that location.
Other people can see your picture on their phones by texting Blockies the sticker code, or they can add photos to any sticker, making a photo album of that spot, and all pictures are archived on Blockies.com.
To retrieve a photo message, just send an SMS to firstname.lastname@example.org that says “get UNIQUE CODE.” Your phone will receive a picture message that someone else left on that sticker, or a link if your phone cannot receive picture messages.