Quora raises $80m, takes valuation to a reported $900m

The investment round values the firm at $900m, according to sources cited by tech news site Re/code.

Quora raised $50m in May 2012, and $11m two years before that.

Through its website and mobile app, Quora allows users to ask questions of each other. It has positioned itself as a place for professionals to share expert knowledge.

Pictured are Quora founders Adam D’Angelo and Charlie Cheever.