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Research from Nielson Analysts shows one third of Americans follow celebrities online, so its not surprising that stars have realized they can monetize their digital presence.

Mariah Carey, 50 Cent, Lindsay Lohan, Charlie Sheen, Paris Hilton, Chris Brown, Snoop Dogg, Snooki, Nick Cannon and Lauren Conrad are just a few of the stars who are paid to tweet to their millions of followers.

In the past, companies had to dish out millions of dollars for celebrities to endorse their products on television, radio or in magazine ads. Now, data shows that consumers no longer pay much attention to traditional advertising, but they do follow famous people. The result: advertisers are paying stars a fee to blast out a promotion to their online fan base, in 140 characters or less.

The marketing agency Adly acts as a middle man distribution business, helping roughly 1,000 actors, athletes and musicians send out sponsored tweets from over 150 advertisers, including AT&T, Microsoft and Sony.

Among its successes was the company's launch of Charlie Sheen's Twitter page, and negotiating a $10,000 per tweet rate for Kim Kardashian.

"Typically those fees will vary from the low four figures to the mid five figures per tweet," Adly CEO Arnie Gullov-Singh told Fox411.

Gullov-Singh said his advertiser clients like the fast results because it's very easy to track the clicks on the actual tweets, the brands' website, and subsequent online conversation.

"If nobody's talking about a brand today and a bunch of celebrities tweet about it, more often than not you're going to see a significant lift in the number of people that will talk about the brand going forward," he says.

But does anyone really go out and buy a Toyota because Snoop Dogg tweeted about driving one?

"People are really not as gullible as the celebrities and the brands think" says Kinsey Schofield, a celebrity ghost tweeter and social media strategist who helps her famous clients build their online presence and write tweets. She tells Fox411 that these ads are actually ruining the experience for the fans.

"It's fun to live vicariously through some of these people, but when you throw sponsorships in the mix, it just kind of makes it less fun. The story telling is no longer there," she said.

Schofield adds that fans may be more accepting of the ads if celebrities overshare and give good behind the scenes scoop.

She said, in the future, actors and actresses may start charging movie studios for access to their huge online fan bases to promote their films.

"Studios are already sneaking into contracts and negotiations that, not only are they having to do global press tours, but they have to do a certain amount of social mentions on all of their social media sites," Schofield said.

Companies and sponsors are also looking for ways to dig deeper into the brand market.

"They'll have a celeb take a picture of a purse, a dress, or CD they like, and then they'll go buy that product in bulk, sell that product through the celebrity, and split the profits with the celebrity,"  Schofield said.

Gullov-Singh adds that celebrity e-mail distribution could be another future trend. He said that there is no doubt that "consumers will continue to follow celebrities, and celebrities will continue to innovate in how they monetize that relationship they have with their fans."