What makes him powerful: Dick Costolo took over the Twitter helm from co-founder and CEO Evan Williams in early October. During his 24-month tenure at the top, Williams steered the microblogging platform from cult phenomenon to mainstream media juggernaut, revolutionizing how users interface with the world at large. The challenge facing Costolo is not only sustaining Twitter's momentum but also monetizing it. The former doesn't appear to pose any problems: Twitter now boasts 175 million registered users worldwide, up from 503,000 three years ago and 58 million only last year. Moreover, roughly 370,000 new users are signing on each day. And while it's far too early into Costolo's stint to pass judgment on his business acumen, experience is on his side. Prior to joining Twitter as COO in 2009, he founded FeedBurner, a startup providing media distribution and audience engagement services for blogs and RSS feeds. Google acquired FeedBurner in 2007 for a rumored $100 million.
In his new role, Costolo will continue expanding the advertising initiatives Twitter first introduced this spring, chief among them the Promoted Tweets program. Promoted Tweets show up when users search for keywords tied to advertiser campaigns. From there, Twitter inserts user-relevant promotional posts based on metrics like geographic location or shared interests among followers. The Promoted Tweets concept hinges on what Twitter calls resonance--the company measures ads according to nine factors, including the number of users who see the ad, the number who reply to it and the number who pass it on to their followers. If a post does not achieve a pre-defined resonance score, Twitter will no longer show it as a promoted post, meaning users will not see ads they don't find useful; in addition, advertisers will not have to pay for posts that are removed. Costolo's first major move: A consumer trial integrating Promoted Tweets directly into user timelines, launched earlier this month.
Twitter also continues to roll out Promoted Accounts, a solution enabling marketers to boost their audience by paying the firm to automatically suggest that users follow brands with similar interests. According to Costolo, the idea behind Promoted Accounts is to give businesses new opportunities to get informational updates in front of consumers, not just ads. But not all of Twitter's sponsored efforts have hit paydirt: In late September, the firm abruptly shut down Earlybird Exclusive Offers, which promised time-sensitive deals to users who follow the @earlybird tweet stream.
In addition, Twitter made several key acquisitions over the last 12 months, most notably scooping up Atebits, developer of the Tweetie client for iPhone. The company subsequently renamed Tweetie "Twitter for iPhone," later introducing branded clients for the BlackBerry and Android operating systems as well. Twitter credits the strategy for increasing its total number of mobile users 62 percent since mid-April, adding that 16 percent of all new users now begin tweeting on mobile devices, compared with 5 percent before it unveiled its first branded smartphone client. Moreover, 46 percent of all active users now make mobile a staple of their Twitter experience. That's undeniably impressive, but there's still room for significant growth--and if Costolo can vault Twitter to the next level, his mobile industry stature will grow as well. --Jason