Who he is: Jack Dorsey is Twitter's Executive Chairman, and perhaps the best known Twitter exec thanks to his public actions and involvement in other headline-grabbing efforts like mobile payments venture Square.
Dorsey was on the engineering team of the podcasting company Odeo, and as that company death-spiraled after Apple adopted podcasts directly into iTunes, Dorsey hatched the idea of a kind of SMS-based social network. Twitter sprang from this idea—a dramatic turnaround from when a seemingly despondent Dorsey was reported as saying "I’m going to quit tech and become a fashion designer" at about this same time. Dorsey is an occasionally controversial entrepreneur, having been called "difficult to work with."
His relationship with Twitter: Dorsey is currently executive chairman of the company, and is credited as being a cofounder. But it's not alway's been a happy relationship, and recent revelations about fights among the core staff in the early days of the startup paint a darker picture of Dorsey than is typically portrayed. He was forced out of the company at one point by his business partner Ev Williams.
What he's worth now: It's not entirely clear, but Dorsey's been regularly thought by Forbes to have a net worth of over $1 billion.
What he’ll earn via Twitter’s IPO: Dorsey owns 23,411,350 Twitter shares according to the S-1 report. Since Twitter's day one closing price was $44.90 Dorsey is worth something like an extra gazillion dollars. We kid: It's more like $1.05 billion. Still, that's not chump change.
What he’ll likely do with the money: Dorsey is just 36 (his birthday is coming up November 19th), and it would seem unlikely he'll just sit back with his money. Given his enthusiasm for innovating, and the fact that Square still has a long way to go to change the mobile payments game—despite the hype—we're betting Dorsey may realize some of his cash and use it to propel his innovations forward.