I have many friends on Facebook who talk fondly of their job. I have a friend who works at Nike World Headquarters and it is interesting to see what goes on there. But the employee should also show some tact and realize what they put out there will be seen. They should have enough common sense to not write anything negative and they should be under the assumption their employer will see it.
I would have to start my argument with three words that we all know all to well. Freedom of Speech! This is used for virtually almost everything. I believe you should be able to voice your opinion on facebook whether good or bad about your employer because that is your opinion. However I don't believe you should be giving out any valuable information because the unethical.
In a free society, anyone should be allowed to post information on the Internet about anything they want. This right should remain legal, even when employees are discussing their employers. People should be careful, however, not to offend anyone or to say anything inappropriate. There could be social implications to their posts.
Employees can be allowed to make their opinions on Google and Facebook status updates. That doesn't mean someone should do that. If your boss finds out you are disparaging the company online while working for said company, that's a least a write up which may lead to eventual termination. It's quite simple: don't bite the hand that feeds you. Your boss can fire you for not being a team player. If your social networking status reflects this, best of luck to you.
No, employees should not be allowed to make posts about their opinions of their employers on the internet, because that could reflect poorly on the company. An employee of a company should not complain about it online. Also, the employee risks telling company secrets, or other things that the company does not want discussed.