Facebook board member leads $50m investment in Quora

Through its website and mobile app, Quora allows users to ask questions of each other, but while similar apps like Wayin and Thumb (formerly Opinionaided) are aimed more at the consumer end of the market, Quora has positioned itself as a place for professionals to share expert knowledge.

Quora was founded in 2010 by former Facebook employees Adam D’Angelo and Charlie Cheever (pictured). In its first funding round it raised $11m, valuing the company at $86m. This most recent Series B round values the business at $400m.