The "Celebrity 100" is an "annual ranking of fame and clout," as Forbes put it. It counts the number of press clips, magazine cover, television appearances and web hits are all taken into consideration.

Although 20-year-old Britney ranked only 25 in terms of earnings, ($39.2 million this year), her almost one million Web hits and 10 magazine cover stories (two of which were in Forbes) made her number one overall.

"She doesn't have Steven Spielberg's pull [he ranked third], but in the last year she arguably had a bigger impact on pop culture," the magazine writes in its latest issue, which hits stands Monday.

This is not very surprising, taking into consideration that the singing diva already has three multi-platinum album under her belt and added film into her resume with her debut at "Crossroads."

She is also a spokesperson for Skechers and made the Pepsi commercial a "commercial hit" (no pun intended). She even has a video game created and named after her.

Together with Britney, Tiger Woods, Steven Spielberg, Madonna, U2, NSync, Mariah Carey, Oprah Winfrey, Michael Jordan and Tom Hanks made up the top ten celebrities, with the band U2 the only non-American in the list.