SAN FRANCISCO (CNNMoney.com) -- Twitter co-founder Evan Williams closed the Web 2.0 Summit in San Francisco with a candid talk late Wednesday, in which he said the microblogging service has plans for a profitable future.
Conference moderator John Battelle pointed out Williams was unable to answer questions about a revenue stream at last year's conference. "But now, it seems like you have the beginnings of an answer," Battelle said.
Williams admitted it took time to introduce "promoted" tweets and trends, which serve as advertising, but he said the company had reason to be cautious.
"We can't put something in front of people if they don't care about it -- not everything would work as a promotion," Williams said. "But now, promoted trends increase conversation about that topic by 3 to 6 times. "
Williams wouldn't comment on specific dollar figures, but he said that "the math looks good" on the promoted products and most advertisers come back.
"There's a million ways to make money on Twitter, though," Williams said, shrugging. "I'm sure we'll try more."
With the business model partially taken care of, Twitter is focusing in improving its product. The company rolled out "New Twitter" this summer, which includes a different layout and social features like "Who To Follow" (Williams commented dryly that the latter "is grammatically incorrect").
"We're in a transitional period -- before, we spent very little time improving the product," Williams 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."
Williams himself has been in transition at Twitter, as he's in his fourth role at the company. He recently handed the CEO role to former COO Dick Costolo, to free himself up to focus more on Twitter's product and design. Williams commented at the conference that "being the CEO of a private, venture-backed company is a sucky job."
Part of Twitter's transition has involved partnerships with other tech companies. Last year, Twitter landed deals to incorporate its streams into searches on Google and Microsoft's Bing. Yahoo later joined that group, and Williams said the demand for Twitter's data far outweighed supply. So Twitter signed a deal with Gnip to sell parts -- but not all -- of Twitter's "firehose" of data.
There's one deal Twitter can't land: Facebook. Currently, Twitter users can set their tweets to update their Facebook statuses simultaneously. But Facebook won't allow it to be a two-way street.
"We'd like our users to be able to fully interact with Facebook, and we're in talks with them often," Williams said. "So far we haven't worked something out. But, I mean, I understand their position. Their social graph is their core asset."
Twitter is also working on creating a better photo experience. There's a few lines the site won't cross: Williams said he "can't really see us making games."
The "biggest focus," he said, is on relevance. All tweets have a secret "resonance score," Williams revealed, which tracks "how much people are engaging [with a tweet] in relation to what we expect."
"We want to optimize 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?"
Williams' proudest achievement with Twitter, he said, is that the service lowers the publishing barrier to zero.
"I don't think the world is actually ready for everyone to have a voice," Williams said. "Not everyone does it right. But I think the open exchange of information has a net positive on the world." Twitter's environment can be highly noisy, Williams readily admitted, but he doesn't think that takes away from the platform's power.
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