PopUp is Twitter for Places : A Mobile Platform that lets brands engage with their fans using location-based push messaging.
With a veteran entrepreneur at the helm and two young guns developing product, PopUp is redefining mobile communication--bringing PLACE to the table. PopUp lets people leave notes at places for friends: simple, yet powerful. Consumers can engage with friends/followers and advertisers can reach customers at the place their message is most valuable and compelling. This opens up a brand new type of location-based communication.