Twitter CEO Dick Costolo stepped down today from his leadership post at one of the Web's top companies, where his leadership has been under scrutiny for months. In a dramatic return, co-founder Jack Dorsey, also CEO at payments company Square, is taking over as interim CEO, according to Twitter.
"I am tremendously proud of the Twitter team and all that the team has accomplished together during my six years with the company," Costolo said in a statement today. "We have great leaders who work well together and a clear strategy that informs our objectives and priorities. There is no one better than Jack Dorsey to lead Twitter during this transition."
The micromessaging platform has become a cornerstone of Internet culture but has also been plagued by slow adoption by a wider audience. The app has been overtaken by Instagram in terms of monthly users and, in terms of public perception, by apps like Snapchat and Pinterest.
Last quarter, ad sales failed to meet even Twitter's own forecasts, and Wall Street has been growing restless for a change. Most recently, early investor and top Silicon Valley player Chris Sacca came out with a long critique of the company and suggestions for how to make it better for new users not accustomed to its short-form communication and overwhelmed by the flood of content.
That's not to say Costolo's tenure has been all bad. He presided over a company that has controlled a new form of content distribution, attracting most every major brand and media company. He helped create partnerships with the NFL and NBA, among other top entertainment entities, who use the platform to share their videos and sell sponsorships.
The ad business is expected to reach $2.3 billion in revenue in 2015, up from $1.4 billion last year. Still, calls for Costolo's ouster have grown louder mostly because of slow user growth. Twitter barely tops 300 million monthly users, while Facebook continues to reach new heights with 1.4 billion and rising.
"Dick has put a world-class team in place and created a great foundation from which Twitter can continue to change the world and grow," Dorsey said in today's statement. "We have an exciting lineup of products and initiatives coming to market, and I look forward to continuing to execute our strategy while helping facilitate a smooth transition as the board conducts its search."