SAN FRANCISCO: Brands using Twitter's "promoted tweets" service have substantially increased their buzz levels across its pages, according to Evan Williams, the site's co-founder.

Twitter has built a global userbase of 175 million and now offers companies the chance to buy "promoted" tweets and trends, securing original partners including Virgin America and Bravo.

Williams suggested the early results of the service, launched earlier this year, were extremely promising, not least because Twitter initially adopted a cautious strategy.

"We can't put something in front of people if they don't care about it - not everything would work as a promotion," he said.

"But now, promoted trends increase conversation about that topic by three to six times.

"The math looks good, and most of the advertisers are coming back and they're buying more."

Although this approach has been successful, Williams argued other opportunities may be explored.

"There's a million ways to make money on Twitter," he said. "I'm sure we'll try more."

One monetisation opportunity is an in-house analytics system, such as providing guidance on creating "compelling" messages, which is currently being tested with a small group of corporate customers.

It also recently signed a deal with Gnip, a specialist in this field, to sell selected portions of the "firehose" of data available across its pages.

Elsewhere, Williams revealed Twitter rates each member in terms of their overall standing, as part of the "Who to Follow" feature.

"We've got a reputation score for every user," he said. "It's sort of like listing a page rank."

Similarly, all "tweets" receive a "resonance score" indicating "how much people are engaging in relation to what we expect."

"We want to optimise for return on attention," Williams said. "There's 100 million tweets a day, so which matter to you? How do you get the most out of it?"

Another of the company's objectives going forward is striking deals with Facebook, the world's biggest social network.

"We'd like our users to be able to fully interact with Facebook, and we're in talks with them often," said Williams.

"So far we haven't worked something out. But, I mean, I understand their position. Their social graph is their core asset."

Williams predicted Twitter would continue innovating, after redesigning its website, adding new tools like the ability to watch video.

"We're in a transitional period - before, we spent very little time improving the product," he said. "That's because we had to spend all our time scaling.

"We got to a point earlier this year where we actually had time and resources to do some improvements."

Data sourced from CNN/CNET; additional content by Warc staff