Eight companies are reportedly providing the government's National Security Administration with back-end user data access through the controversial PRISM program, as uncovered this week by the UK Guardian and Washington Post newspapers.  Noticeably absent, Twitter.

Here's how numerous online networks rank in terms of security and privacy concerns, as ranked by the Electronic Frontier Foundation.

Read more on Mashable at http://mashable.com/2013/06/07/nsa-prism-twitter-privacy/.