Twitter: Next Stop, Some "Tweet" Revenues?

Sitting on a $50-million cash reserve, how should Twitter generate revenues? Targeted ads like Google? Job ads like LinkedIn? Enterprise editions with private labeling, enhanced security, performance guarantees and service level agreement (SLA) support, and fee-based support? I'm just free-styling here, but they've got to do something, so what should it be? E-mail me at medortch@dortchonit.com, tweet me publicly or @dortchonit, and/or leave a comment here, and let's see if we're as clever as Twitter management or Twitter's investors.