Twitter co-founder Evan Williams has stepped down as chief executive of the social media giant amid speculation over the sites future ownership.
Williams will be replaced by Dick Costolo in a move heralded as marking a shift in emphasis for a site which is transitioning from a startup business to one with potential to rake in substantial sums of money.
Most recently this saw the firm begin to raise cash by offering search access to its tweets to search engines Google and Bing. Twitter has also launched so called 'promoted tweets' whereby paid for tweets are given priority in related search listings.
Similar priority is given to products paid for by advertisers and promoted accounts which are suggested to newly registered tweeters.
Writing on the Twitter blog Williams said ""Growing big is no success, in itself. Success to us means meeting our potential as a profitable company that can retain its culture and user focus while having a positive impact on the world. This is no small task. I frequently reflect on the type of focus that is required from everyone at Twitter to get us there."
That focus will see Williams focus his energy on product strategy, an area he describes as his "passion."