"To become a celebrity is to become a brand name," Philip Roth said more than 20 years ago.
He was right, of course, but the novelist wasn't thinking big enough. Exploited correctly, celebrity can be converted into something more durable than a mere brand. That is indelibly evident in this year's annual ranking of fame and clout, the Celebrity 100.
Hollywood talent-manager-turned-producer Brad Grey leverages the star status of his actors to increase his own pull at the bargaining table. David Letterman uses the perks of late-night fame to produce TV hits in prime time.
Money is still the most important metric of celebrity, and we calculate which entertainers and athletes have earned the most in the past year. But the measure of celebrity entails much more — media mentions and Web buzz and other touchstones of fleeting fame. Thus our Power 100 list combines earnings with media exposure to calculate the relative status of a vast array of stars.
This year's champ: Britney Spears. She doesn't have Steven Spielberg's pull, but in the last year she arguably had a bigger impact on pop culture. Celebrity is at peak value in the present, but these days even minor stars can extend their fame for decades. Some still make money milking the last bit of adulation from fans at autograph shows.
Britney won't be selling her signature anytime soon, but it is nice to know she will have the option. Just in case.
The Top 10, plus our list of "one-year wonders."
• For the full Celebrity 100 list, go to Forbes.com
For more, go to Forbes.com..