From The New York Times:
Andrea Stroppa and Carlo De Micheli, two Italian security researchers, spent the last several months investigating the underground economy for Twitter followers and said they had found a thriving market.
There are now more than two dozen services that sell fake Twitter accounts, but Mr. Stroppa and Mr. De Micheli said they limited themselves to the most popular networks, forums and Web sites, which include Fiverr, SeoClerks, InterTwitter, FanMeNow, LikedSocial, SocialPresence and Viral Media Boost. Based on the number of accounts for sale through those services — and eliminating overlapping accounts — they estimate that there are now as many as 20 million fake follower accounts.
Fake followers are typically sold in batches of one thousand to one million accounts. The average price for 1,000 fake followers is $18, according to one study by Barracuda Labs. Mr. Stroppa and Mr. De Micheli said some sellers bragged that they made $2 and $30 per fake account. A conservative estimate, they said, was that fake Twitter followers offered potential for a $40 million to $360 million business.
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