"Our plan is to develop new projects and work on solving big
problems." The move, however, marks the latest "musical-chairs shuffle at Twitter, which is undergoing a leadership overhaul as the 5-year-old venture matures from a start-up to a tech industry power
player," writes CNNMoney.com. In October, COO Dick Costolo took over Evan Williams' role as the company's CEO, while Williams agreed to focus on product development. Soon after, however, Williams
relinquished day-to-day involvement at the company, while the once estranged co-founder Jack Dorsey returned to lead product development.
"The Twitter crew and its leadership team have grown incredibly productive," Stone wrote in his blog post. "I've decided that the most effective use of my time is to get out of the way until I'm called upon to be of some specific use."