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

Drug firms fear that being "liked" on Facebook could get them in trouble with the FDA. iStockphoto.com hide caption

itoggle caption iStockphoto.com

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