A judge has ordered that five employees who voiced complaints on Facebook be reinstated to their jobs and be awarded backpay.  The five employees of Hispanics United of Buffalo complained about the workloads and other conditions of their job.  HUB is a non-profit agency in Buffalo, New York.  Their supervisor then fired them, saying their Facebook posts were harassing a co-worker.  The Director, however, did not fire his secretary who also posted a complaint.  

One of the five filed a complaint with the National Labor Relations Board.  The NLRB enforces the National Labor Relations Act.  The NLRA comntains a provision that prohibits employers from taking action against employees who discuss "terms and conditions" of their job.  Discussing terms and conditions of a job is seen as leading up to forming a union, which is protected activity.  The NLRB judge eventually agreed with the employees.  See NLRB decision.  

There have been many complaints like this one regarding web based complaints.  I discussed some of them here and here