Twitter CEO Evan Williams steps down, replaced by COO Dick Costolo

News Core - Twitter CEO Evan Williams announced Monday that he is stepping down from his position and will be replaced by Twitter's current Chief Operating Officer Dick Costolo.

Williams made the announcement on the company’s official blog.

"I am most satisfied while pushing product direction. Building things is my passion, and I’ve never been more excited or optimistic about what we have to build,’ Williams says in the blog posting.

"This is why I have decided to ask our COO, Dick Costolo, to become Twitter’s CEO. Starting today, I’ll be completely focused on product strategy.’

Williams, 38, who also founded Blogger, a popular web blogging site, before creating Twitter with Biz Stone and Jack Dorsey, became CEO of Twitter in October 2008.

In the blog posting, Williams announced that Twitter currently has over 160 million users and its workforce has grown to 300 employees. He described Costolo as a "critical leader’ and a ’three-time successful CEO.’

According to Mashable, a popular technology blog, before arriving at Twitter, Costolo was the co-founder and former CEO of Feedburner, which was later acquired by Google.

Williams ended the blog posting by saying: ’I’m extremely proud of how far Twitter has come in the last two years. And, I couldn’t be more excited about where our amazing team will take it next.’