Snapchat Geofilters are the first truly mobily ad format. The opportunity with filters is incredible. Once I started using it and buying filters for clients I started seeing all the awesome opportunites. This could have been such an easy opportunity for many location sharing apps like Foursquare/Swarm. Fully expect many other services with photo/location sharing will start adopting the format. I suspect Twitter’s recent option to add stickers to photos is an obvious copy of this.