MeshForum is showing Art projects in between speakers – the current one is Yellow Arrow, which is a kind of tagging project where yellow arrow stickers and unique IDs are used to tag and point to items in the physical world. The tags can be referenced online.
Tags are sent with cell phones and text messages. If you find a tag, you can send the number and get information about the tag back to your cell phone via text message.
It has similarities to the Grafedia project.