From the website:

PMbuzz was built for the nightlife community. It’s where the out late crowd mixes it up with clubs, DJs, promoters and entertainers. Get the word (pictures, music and video) on the street from the people making the scene. Join your favorite clubs’ crowd (sort of a friends list for clubs) to get notified of events as they’re listed. Use your calendar to find out which of your friends is planning to be there. Blast a message out to your crew to let them know where to meet and when.