For the past few years, Dallas-based digital marketers Agency Entourage have compiled information on some of the social and digital aspects of the SXSW Interactive festival, including its rapid and massive growth. They've tracked attendance, @SXSW mentions, average tweets, Foursquare check-ins (after it launched in 2010, of course), and emerging trends, and then threw it all into one big, visually-appealing infographic that they kindly shared with Billboard. Tracking data since 2009, it's worth a look, and we've included it below.

Jay-Z, Mashable, Jared Leto Sightings: SXSWi Social Media Post-Mortem

Read's 2012 SXSW Blog