Katherine Leon says she spends up to 12 hours a day online interacting with others who share her rare heart condition. Emily Bogle/NPR hide caption

itoggle caption Emily Bogle/NPR

Employers have been asking for prospective employees' Facebook username and passwords to do some extra research on whom they may be hiring. Leon Neal/AFP/Getty Images hide caption

itoggle caption Leon Neal/AFP/Getty Images

Google Plus makes it easy to group friends into "circles" and share information with only specific people. The million dollar question: Will enough people try another social network? AP hide caption

itoggle caption AP