Thanks to the feedback on my previous post, I was introduced to Jambo. Jambo is an evolution in social software; forgoing the closed-loop environments of other social sites (del.icio.us, flickr, etc.) and instead offering an open broadcast of your social information. It lets you connect with others in your vicinity (through WiFi) who may have similar interests, are previous acquaintances, or who simply are responding to your public tagline ('Anyone up for tennis?' is offered on the Jambo homepage).
Download Jambo at www.jambo.net