Curious what cellphones your favorite celebrities use? Take a look at their Twitter feeds.
Oct. 19 was a good day for Heidi Montag--and for AT&T. That was the day the wireless operator gave the reality show actress and aspiring singer a BlackBerry Bold in a striking new color--white. Montag posted a photo of the phone on her Twitter account with the caption, ''I LOVE it!! My new phone!''
Within minutes, dozens of Montag's 690,000 Twitter followers clicked on the photo and expressed their approval, calling the phone amazing, gorgeous and stylish. One noted, ''AT&T always has the best phones,'' while another joked, ''I think I know what I'm getting when my T-Mobile contract is up!''
To a carrier like AT&T--and BlackBerry maker Research In Motion ( RIMM - news - people )--that kind of publicity is golden. To elicit it, they ''gift'' or ''seed'' products for free to celebrities at concerts and award shows or via mail or messenger service. The practice isn't new, but the rise of micro-blogging services like Twitter make it easier than ever for companies and fans to keep tabs on the cellphones that celebrities use. Previously, consumers had to rely on in-person sightings, paparazzi photos and celebrity interviews for clues.In Picture: Cellphones Of The StarsIn Pictures: Killer Apps: Best Branded Mobile ApplicationsIn Pictures: Worst Branded Mobile ApplicationsIn Pictures: 10 Fun Ways To Shop OnlineIn Pictures: The Year's Biggest Data Disasters
On Twitter, tracking mobile preferences can be as simple as watching for a tweet (or message) like Montag's that refers to a particular phone. For celebrities that are less effusive (or exhibitionist) than Montag, a quick read of their Twitter status line usually offers insight. That's because Twitter cites, by name, the method or software used to post messages. Those programs, in turn, often reveal what kind of phone--or what kind of mobile operating system--sent the update.
Consider John Mayer. The singer, who updates his Twitter account multiple times a day, has been utilizing a program called Twittelator for many of his tweets. The software was created specifically for the iPhone, making it easy to deduce that Mayer uses an iPhone, at least part of the time.
Other celebrities leave similar clues. Lance Armstrong, Katy Perry and Jessica Simpson employ UberTwitter to post messages to their Twitter accounts. The service works only on BlackBerrys, pegging them as BlackBerry users. Mariah Carey and Oprah Winfrey mostly update from the Web, but occasionally use TwitterBerry--another BlackBerry Twitter program.Image: Heidi Montag-Pratt Text and images: Copyright Forbes.com Any unauthorised reproducton is prohibited.