When considering the most popular Twitter users, Britney Spears is not likely to be the first name that pops into your head. But, believe it or not, the on-again-off-again pop star is Ashton Kutcher’s biggest threat when it comes to gathering the biggest crowd of followers. And while Kutcher was the first person to get 1 million followers, Spears has one-upped him in becoming the first twitterer with 5 million followers. The most ironic part of Ms. Spears’ massive online popularity, though, is that it’s mostly for show; unlike some celebrities’ Twitter accounts, which are operated independently by the celebrities themselves, Spears’ account is managed by her management. This means that the less-than-regular PR tweets are augmented by even-less-than-regular tweets from Britney herself.