First introduced at SXSW, proximity based social network LoKast is starting to gain some traction in the music community.  The iPhone app has reached 125,000 downloads and 30+ bands like Third Eye Blind are using it to share content with fans during their shows.

LoKast, short for “local-casting,” allows users to create a profile with selected photos, contacts, videos, web links and music from their iPhone. When another LoKast user is within 300 feet, the app automatically discovers them and enables them to share and download content.

Several bands used LoKast to distribute excluisive content during their performances at Coachella, and LoKast designed a special portal within the app so fans could download goodies from many of the DJ's performing.  I'm not vouching for some of the acting in this video, but it provides a decent overview: