Twitter today rolled out an enhancement to its Promoted Tweets paid ad service that enables marketers to target a subset of consumers.

The microblogging service previously required a marketer to initially post a message, called a tweet, to all its consumers. Then the marketer could target it at a specific customer base. However, that was impractical if the post was specifically focused on a single market like New York, for example.

“What if you want to make an offer just to New York Twitter users?” wrote Kevin Weil, Twitter’s product manager in a blog post. “Until today, it’s been impractical to send these kinds of highly tailored tweets, since there was no way to reach people in New York without also reaching followers in Norway, Nebraska and Nigeria who can’t take advantage of your offer. Today we’re introducing targeted tweets, an enhancement that enables brands to reach specific audiences on Twitter without first sending a tweet to all followers.”

Promoted Tweets appear in a consumer’s timeline like any other tweet. Like a regular tweet, the messages will appear in the timeline once; as the shopper scrolls, the Promoted Tweet flows with the rest of the tweets in the timeline.

Advertisers can now post a Promoted Tweet based on a consumer’s location, device or platform, such as iOs, which would enable a message to be seen only by users of Apple Inc.’s mobile devices.

As with all Promoted Tweets, advertisers pay for targeted tweets only when users engage with them, and the tweets that generate the most engagement are likely to appear more often.

The move is the latest effort by Twitter to bolster its advertising revenue, which is estimated to hit $259.9 million this year, according to research firm eMarketer. Earlier this year, for example, it rolled out mobile ads.