Can you be fired for posting to Facebook, Blogs, or other sites?

 Workers Rights Extend to Facebook
Company Accused of Firing Over Facebook Post "...“Employers should review their Internet and social media policies to determine whether they are susceptible to an allegation that the policy would ‘reasonably tend to chill employees’ ” in the exercise of their rights to discuss wages, working conditions and unionization. ..." Reference: www.nytimes.com