Monetising fame is actually pretty easy.
Consider the Oprah effect. When Oprah recommends a book, it sells like crazy. If she wanted to, she could leverage her fame to promote products, businesses, and more in exchange for a cut of the sales. Lots of companies would be happy to pay her for an endorsement.
The Catholic Church is excellent at leveraging fame to make money. The Church has many supporters who go out of their way to market it.
This generates new subscribers who are in turn encouraged to go out and spread the “good news.” By taking the form of a non-profit, they also avoid many taxes. L. Ron Hubbard copied their model to create the Church of Scientology, which is also quite wealthy.
Celebrities commonly generate income streams by endorsing products and services. With enough leverage they can be granted a cut of the sales they help generate, stock options, and additional perks. Their endorsement may not involve much direct effort, maybe a photo shoot or some filming, but it can produce significant income if the celebrity’s recommendation carries a lot of weight in terms of generating sales.
Many celebrities have millions of Twitter followers, even though they often share mostly personal updates that no one would ever want to read if it came from a non-celeb. With such large audiences, they could recommend all kinds of things that make them money, such as William Shatner did by appearing in Priceline commercials. Movie stars can promote their own movies too, which puts more money in their pockets if they can help sell more movie tickets.
Fame provides many benefits because attention begets more attention. A famous movie star gets more movie offers because the star’s fame can drive more people to see the movie. More movies means even more fame and recognition.
You don’t have to become a major movie star to enjoy some of the benefits of fame. Even a little fame can help. For instance, due to the popularity of my website, I’ve been approached by local entrepreneurs. My website has been mentioned in quite a few places too. I’ve never paid for any of this extra publicity. More exposure can generate more web traffic, and that’s something I already know how to monetise. I don’t have a good way to measure how much this helps income-wise, but I’m sure it has some effect.
You have to be careful when monetising fame because there’s always a chance of killing the goose that lays the golden eggs. If you do something stupid that kills your reputation and turns everyone against you, your fame will become infamy. Interestingly, you can still monetise infamy, but you may need to use different strategies. The greater risk to your financials is muddying your reputation and being forgotten.