With more than a billion unique visitors each month, YouTube is an attractive venue for brands to reach consumers -- but its default tools aren't always sufficient for enterprise companies.

That's why Zefr has seen such success building a set of social marketing and rights management services on top of the video-streaming platform. The company, which today announced $30 million in new venture funding, makes cloud-based software brands can use to track not only their content but relevant content uploaded by fans.

In addition to analytics -- it offers plenty of stats on sentiment and engagement -- Zefr also enables brands to identify and claim "infringing" content, turning it into a source of revenue by serving ads over the videos. (Piracy can be a win-win situation after all.)