SAN FRANCISCO - A research firm expects Twitter's ad revenue to double this year as the online messaging service delivers more marketing pitches aimed at consumers using smartphones and tablet computers.
In a report issued Wednesday, eMarketer projected that Twitter's worldwide ad revenue will climb from an estimated $288 million last year to $583 million this year. In 2014, eMarketer predicts Twitter's ad revenue will approach $1 billon.
EMarketer believes mobile devices will account for more than half of Twitter's ad revenue this year.
The research firm makes educated guesses about Twitter's revenue based on market trends and data. Twitter, based in San Francisco, is privately held and doesn't disclose financial figures.
Twitter hasn't set a timetable for an initial public offering of stock.