San Francisco-based Twitter announced that five partners are using new software that automates and streamlines advertisements displayed as "tweets" and promoted to high profile positions in user feeds.

"We've been testing the Twitter Ads API since January with our partners, and today we're officially launching it," revenue product manager April Underwood wrote in a blog post.

"Marketers now have more tools in their arsenal to help them deliver the right message, to the right audience, on the desktop and on mobile devices -- all at scale."

Twitter started the year with more than 200 million users and a prediction by industry-tracker eMarketer that the company's annual revenue would top $545 million.

The first companies using Ads API (application programming interface) software include computer software veteran Adobe and cloud computing triumph Salesforce.com.

"As interest in Twitter has grown, our focus has been on delivering better ads for users, not more ads," Underwood said.

"Our system rewards marketers for being good, not for being loud."

In August of last year, Twitter began letting advertisers aim "promoted tweets" at users based on the interests they express in their messages.

Twitter ad products tap into a "real-time interest graph" to target the terse promoted messages in hundreds of categories ranging from gardening and hobbies to pets and investing.

Factors that go into determining interests include which Twitter accounts people follow, such as sports teams or chefs.