Box, which filed for a “secret IPO” not too long ago, is on track to double its revenue this year to $200 million or more, at least according to Bloomberg’s anonymous sources.

The Los Altos, Calif.-based company was founded by Aaron Levie, its charismatic CEO and his college friend Dylan Smith, who is CFO, in 2005 and has made a splash pushing its file-sync-and-share service as an enterprise-friendly alternative to Dropbox, which pretty much set the standard for file sharing and cloud storage in the consumer space.

Box claims some big accounts including Proctor & Gamble, Six Flags, Avaya, Hearst Corp., Stanford University and others.

The big question for Box (and Dropbox for that matter) is how many of its users pay for the service. There’s a free version for individual users as well as paid tiers for companies.

The company’s prospectus is due out soon, so maybe some of…