It is a big moment in a start-up’s life when the founders realise that they have to step back and hand the power levers to someone else. Twitter co-founder Evan Williams did that last night when he said he was handing over the CEO reins to COO, Dick Costolo.

Williams says he will instead focus on strategy and developing Twitter as the pace of change and development continues at a increased tempo as user numbers grow, the focus on monetization increases and a snazzy new look web interface unveiled being some of the things we have seen in recent weeks.

Williams said that the redesign has by and large had great user feedback. And it is good, but it is only a leap into the present. Twitter still needs to look at creating a desktop app and I don’t quite understand why it hasn’t tackled this…yet. I’m sure the changes at Twitter that this management shake-up will see to that as Williams focuses on product strategy, which has been Twitter’s weakness. That weakness (and its fledgling state) helped to create the Twitter ecosphere and a sea of third party apps.

Appointing Costolo as CEO is the next step for company that went global with only a handful of staff. It now has  300 people working at Twitter today compared to 20 when Williams took the CEO job two years ago.

In that same period of time it has gone from 1.25 million tweets a day to 90 million; from three million registered users to more than 165 million. That Williams says presents a huge challenge in terms of management as Twitter attempts to forge itself into the media firm that it can quite easily be in the next five years.

However, one of the key challenges in that time frame will be 1) continuing to develop Twitter (new apps and features); and, 2) hitting profitability as without those two Twitter has no long term future and can not continue to grow and expand. That’s what Costolo’s appointment is about.

In a blog post Williams admits that growing big is not in itself success rather success for Twitter means meeting its potential as a profitable company that can retain its culture and user focus while having a positive impact on the world. That is, he writes, no small task.

“This led to a realization as we launched the new Twitter. 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.

“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 said that during his time at Twitter Costolo has “been a critical leader in devising and executing our revenue efforts”. He said that Costolo would be even more effective now as Ali Rowghani, Adam Bain, Mike Abbott, Katie Stanton and Kevin Thau have joined the Twitter leadership team and are having a big impact.

People often tweet about TV shows as they’re watching them. Additionally, media companies are increasingly finding new ways to incorporate Tweets into their programs. Take, for example, Jimmy Fallon or the Video Music Awards in September. Tweets aren’t just about TV shows; they are part of them.

Elsewhere, Twitter has also unveiled Twitter for Google TV. Twitter said it has come about organically as people often tweet about TV shows as they’re watching them.

“Additionally, media companies are increasingly finding new ways to incorporate Tweets into their programs. Take, for example, Jimmy Fallon or the Video Music Awards in September. Tweets aren’t just about TV shows; they are part of them.

“We’ve long discussed what the interplay between Twitter and television would look like. As a first step, today we’re announcing Twitter for Google TV. It brings Twitter to a platform that merges the Internet and TV into one experience.”

“This is just the beginning of what could be possible at the intersection of Twitter and television. We’re excited to see what’s next,” Twitter’s Carolyn Penner said.

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