Meet Twitter's billionaires

Biz Stone was also a Twitter co-founder, but he was conspicuously absent from the list of the company's largest shareholders.

Stone was one of the company's most visible leaders in the early days, thanks to the personally written dispatches about Twitter's growth -- signed @biz -- that he sent out to users.

He was also integral in the creation of other blogging platforms from Xanga to Blogger. The co-founder stepped back from day-to-day involvement at Twitter in 2011.

Along with co-founder Ev Williams, Stone began working on a venture created in 2006 called the Obvious Corporation. They later announced a new curated blogging platform called Medium that lets users click to recommend items they like. The highest rated articles gain more visibility.

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