Evan Williams: From zero to 500 million tweets per day

Co-founder and board director, Twitter.

From October 2008 to October 2010, Mr. Williams served as Twitter President and Chief Executive Officer. From July 2009 to March 2010, he served as Twitter Chief Financial Officer and from February 2008 to October 2008, as Twitter Chief Product Officer.

Since April 2011, Mr. Williams has served as Chief Executive Officer of Medium, an online publishing platform, and since October 2006, as Chief Executive Officer of The Obvious Corporation, a technology systems innovator.