By Maggie Shiels
Technology reporter, BBC News, San Francisco
Developers were told they are vital to the future of the service
Twitter bosses pulled out all the stops to calm the nerves of jittery developers worried they will be be put out of business by the company's own apps.
Twitter recently built an app for BlackBerry phones and bought the firm behind Tweetie for the iPhone.
At its first developer conference called Chirp, Twitter announced plans for an app for Android phones.
"We want you to know the fundamental philosophy is not changing with Twitter," said co-founder Ev Williams to the audience of about 1000 developers.
"Twitter has always been about developers," he said. "We have always believed in openness and an open ecosystem and the diversity of ideas and that is not changing."
Applications tied to Twitter were credited with driving 75% of traffic to the website, reveals the company.
Developers have been growing increasingly uneasy as Twitter creates its own version of programs previously provided by third parties and buy ups firms behind hot applications.
To help the audience understand its motivation, Mr Williams showed a video of a young Stanford student struggling to download a Twitter app for her iPhone. Although "painful" to watch, he said it showed it was "really under- serving our users".
"We have to have a core experience on the major platforms just like we have on the web or else we are failing users and failing the ecosystem," he said. "We needed to fix that."
Fred Wilson of Union Square Ventures added to the angst with a blog post telling start-ups to stop filling in holes in Twitter's products and to launch apps that will give birth to entirely new businesses.
Some feared this was code for saying developers faced displacement as Twitter built official versions of these apps.
Loic Le Meur, the founder of Seesmic which competes with Twitter and also provides apps for the microblogging service, said he was surprised by the company's moves.
The first Tweet was posted on March 21, 2006
Twitter says users write 50m posts a day
To date there are over 100,000 Twitter apps
Twitter says 75% of traffic comes via 3rd party apps
"There has been a change of strategy and, while I don't think it will hurt us because we are trying to be less dependent on Twitter, I believe Twitter could have handled things better than they did," he told BBC News.
Mike Uesugi, founder of Social Rewards, said tension between the platform and those who rely on it for a living was not unusual.
"It is always the case even for Google, MSN or Yahoo that when you start developing around it you could be a target for acquisition by them or you could be deleted by them.
"It definitely concerns me with Twitter and that is why all the developers have to position themselves not to totally depend on Twitter or Facebook or whoever."
Twitter took time to emphasise the future it envisions for developers and what they can do to help the service grow.
"Think big" was the cry from Ryan Sarver who manages Twitter's platform.
Twitter is adding 300,000 new users a day
"We want to help push you and challenge you to think bigger and make bigger apps to help change the world and help the different corners of the world communicate."
While developers worried about various segments of their business being eaten away by Twitter, the company also underlined where it felt real opportunities for innovation lay.
"Twitter has always been about mobile with an emphasis on texting," said Mr Williams.
"Today 37% of active users use Twitter on their phones. It should be 100%. We are still excited about SMS because there are four billion phones in the world as opposed to one billion PC users."
Serial investor Ron Conway has invested money in several start-ups that design apps for Twitter and said there was real value in the platform.
"In four short years Twitter has built an ecosystem around itself that is providing a livelihood for all these entrepreneurs," he said. "Twitter and real-time data is in its infancy. The thousand people here merely hint of how big this space is set to become."
The conference also focussed on ways for Twitter to make money - a question that has dogged the service almost as long as it has been running.
While advertising has been the most popular approach adopted by most companies on the web, Dick Costolo, Twitter's chief operating officer, told the BBC it had no plans to go that way.
"Revenue is happening this year" said Twitter's Ev Williams
"We've had offers for significant amounts of money to run display advertising on Twitter and on the ecosystem but we're just not interested in that as a vehicle. It is not innovative. It is not organic to the way people use Twitter," he said.
Twitter has announced plans for "promoted tweets" among a handful of preferred customers like Starbucks and Best Buy. These companies will pay to have their messages float to the top of search results.
Mr Costolo told the conference that Twitter would split the revenue, after costs have been deducted, with the developers of apps that carry these messages.
Another part of the revenue strategy will be paid commercial accounts for businesses. Mr Costolo told BBC News that around 100 companies are trying out the system.
"Think about promoted tweets and commercial accounts as the one two punch of our monetisation engine. If you look beyond those two pieces what you will see down the road is a threading together of the two to give a much richer Twitter.com page and engage customers in a lot more interesting ways."