I just got my new copy of Wired and a short story about YellowArrow.org caught my eye. YellowArrow apparently gives away a bunch of yellow arrow stickers (appropriately enough) and each has a unique code written on it and an email address to text from your cellphone. People then take these stickers and put them up anywhere around the city they want. They can then associate a message with the unique code and when you text YellowArrow you’ll receive that message back to your phone. Want to tell someone about a great little restaurant? Some cool graffiti? Best bar in the city? It’s a really cool way to leave your mark and let people know what you think is worth checking out, or to just get some random person’s opinion on what’s worth seeing or doing. I haven’t actually seen any of these around New York, but I’ll certainly look out for them. Supposedly you can pick up the stickers from those Go Card displays at bars and the like. This sounds like a lot of fun and a great way to create a kind of collaberative travel guide.