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Although Foursquare has experienced amazing growth in its first three years, the social check-in site has gotten a lot of nice traction from high-profile early adopters as well.
Celebrities and technophiles like Ashton Kutcher and 50 Cent have thousands of followers who are interested in where they go and what they like. Unfortunately, many celebrities opt out of some of the platform's major features, like mayorships, in favor of a much more privacy-friendly page.
But for those willing to open up their check-ins to the public, well, let's just say it can get interesting. The luminaries on this list are proof of that.