3. Katy Perry
Twitter handle: @katyperry
Joined Twitter: Feb. 20, 2009
First tweet: Feb. 21, 2009. "Just got into Berlin... feeling better thank you, have my vicks inhaler by my bedside... and P.S. I TWITTTTER! GAH. Such a follower!"
No, the marriage to Russell Brand didn't work out, but the rest of her career after this tweet sure did. The album she'd released a year before, One Of The Boys, went on to sell more than 3 million copies. The follow-up a year later, Teenage Dream, has sold nearly 6 million to date.
Her songs spent more than a full year in Billboard's Top 100, she's had six No. 1 singles during that span, voiced Smurfette in The Smurfs and just had her concert film Katy Perry: Part Of Me land in theaters this summer. Forget about the guy from Forgetting Sarah Marshall, Perry has a lot more to tweet about.