Employees can expect to give up certain rights to privacy that others take for granted. They are not entitled to the same rights of privacy while they are work as they are when they are off the clock.
Technology has made it easier than ever for employers to keep an eye on their employees' activity. Aside from the obvious actions, such as glancing at an employee's Facebook postings, employers can track the keystrokes an employee makes on their keyboard, see where their employees go on the internet (assuming they are using an office computer), monitor an employee's e-mail usage (and potentially read the content) and even track their phone calls and voicemail.
None of these actions are considered an illegal invasion of privacy, especially if the employer provides notification that the company engages in these actions. Employees can, however, have a reasonable expectation of privacy when it comes to their personal computer usage, social media excluded.
An employee is free to talk about anything in e-mails to friends and family without fear of retaliation. For example, an employee may choose to discuss a medical or emotional condition with her friends. If the discussion is limited to phone calls done on her personal phone on her own time, and written communication takes place on her computer via her personal e-mail, her company cannot use this information against her. If they do, it would be considered a direct invasion of privacy. If, however, she has not disclosed the information to her boss and he learns about it through company phone calls or e-mails, he may be able to legally use the information in a way that impacts her ability to do her job.
If you believe that information about you has been obtained illegally and has been used to negatively impact your work, you may wish to contact an attorney who can advise you of your rights.