With the turmoil in Iran making Twitter and Facebook the new journalism, social marketing is all the rage. Concert production company Project 30-90 has been trying to build "buzz," says a PR spokesperson, by announcing "secret" concerts (consisting of one 30 minute set) via Facebook and Twitter just 90 minutes before the show starts. So if you like the Revivalists, get on 30-90's various social networking feeds, and sometime around 6:15 p.m. tonight, you should get a message about the band playing a free show at the secret location at 701 Magazine Street. That's right near the final Wednesday at the Square concert featuring the Hot 8 and Galactic. The PR person also mentioned free cocktails.