NEW YORK (MainStreet) — Have you ever gossiped about a co-worker over email or spent your afternoon on Facebook instead of writing that report for your boss? If you did so on company-owned equipment, your Internet activity may not be as private as you thought. It's not uncommon for companies to monitor their employees' usage of work computers and smartphones and penalize those who violate standards of ethics and professionalism. Here's what you need to know to keep your Internet activity at work in check and avoid trouble with your HR department.

Is Internet Monitoring Legal?

The ability for employers to review employees' emails may sound like a major violation of privacy, but the truth is that doing so is typically well within their authority if you're using their technology.

"If the employer owns the computers and runs the network through which the emailing is being done, then they are generally entitled to access the content depending on state and company laws, most of which favor company rights," says Jennifer Lee Magas, an employment law attorney and vice president of Magas Media Consultants, LLC. "Employers own the content on their own internal email systems and have the right to monitor what you write and to whom."

Your personal email is often fair game, too.

"If employees are using company IT assets to access their personal email at work, the company has a right to monitor that usage," says Daniel Alarcon, HR manager for Calltools.com. "I once had an employee who accessed her personal email on company time to send pornographic images. That is a highly inappropriate use of both company property and company time."

In addition to monitoring email, companies can also track which websites you visit at work for the same reasons—they're entitled to access information that goes through their computers and networks.

Why Companies Are Snooping

While it may seem as though your company is acting like Big Brother by monitoring your Internet usage, doing so helps ensure that employees are behaving ethically and responsibly.

"We want to make sure our employees aren't sending company secrets, harassing other employees or customers and are upholding the professional image on which we pride ourselves," says Alarcon.

Jean Marie Dillon, an HR professional who formerly worked as the vice president of human resources and development for the American Society for Clinical Pathology, recalls a time that she had to review the email account of a worker who was suspected of bullying

"I had an employee approach HR in tears with an anonymous handwritten note in her hand," Dillon says. "The note, left on her desk, was unkind, attacking the employee's mode of dress and her mannerisms."

Although Dillon's HR team recognized the handwriting on the note, more proof was needed to confirm the bully, so Dillon requested access to the suspicious person's company email account.

"The bully was confirmed because emails were pulled that matched the exact tone of the note, and two other employees were discovered participating in the email thread," she says.

How Internet Usage Is Monitored

Truth be told, your human resources department probably isn't sitting around personally reading everyone's barrage of daily emails and reviewing every website that each employee visits. However, if HR is given a reason to be suspicious of a particular employee, it may take the time to read that employee's emails.

While some HR professionals might only read a handful of emails sent by a suspicious employee, others may take more drastic measures.

John Herath, director of human resources for Orion International, says that he has "ghosted" the email account of an employee suspected of wrongdoing—meaning that every email the employee sent or received through the company's email server was duplicated and sent to an email account only Herath could access.

Many companies also use sophisticated software that looks for red flags in emails and other Internet activity—and that software may be running all the time. That means that even if a co-worker doesn't squeal on you for bad behavior, you could still get caught if the software picks up on it.

"My employer has certain software that searches for key words and names, as well as file types," says Alarcon. "Our company firewall also prevents certain websites from being accessed and certain types of files from being received."

Can You Find Out If Your Emails Are Being Read?

Unless you're contacted by your boss or human resources department to discuss any questionable emails, there's probably no way of knowing whether your email account is under review.

"I don't believe that most companies make that information easily accessible to employees," says Tatiana Melnik, a data privacy and security attorney for Melnik Legal in Tampa, Fla. "If you were doing something wrong, employers don't want to tell employees how to avoid the checks."

For instance, if an employer is investigating a workplace harassment allegation, it wouldn't want the person accused to realize that his emails are being reviewed for fear that the person might tamper with evidence.

How to Check Your Company's Policies

It's a good idea to check your employee handbook to find out your company's exact policies on monitoring Internet usage. Some companies even require employees to sign a statement agreeing that they will only use work-issued technology for company business.

"The most legally savvy companies explicitly state in employee handbooks and through corporate sign-on pages that all transacted communications on company servers are the property of the company," says Dillon. "Therefore, when a company has a legitimate reason to screen its property, much like a finance audit, it reserves the right to do so and can without notice. It is not spying."

Could You Be Punished for Your Internet Usage?

While some employees may only be issued a warning for sending questionable emails or visiting inappropriate websites, others could face more serious repercussions.

"It all depends on the violation," says Claire Bissot, HR consulting manager at CBIZ. "If it's trade secrets, it could be grounds for immediate termination."

Employers will sometimes even notify the police about an employee's Internet behavior at work.

"If there's an issue of child pornography, for example, there's a federal law requiring that the employee be reported," Melnik says.

How to Stay Out of Trouble

The workplace experts MainStreet spoke with assured us that most friendly banter between employees over email is perfectly acceptable, as long as it's brief and non-offensive.

"We don't care if there's a quick 'Where would you like to go for lunch?' exchange, but we do frown upon 'Wow, you were really drunk last night!' or non-work conversations that go on for excessive amounts of time," says Alarcon. "The more serious infractions have been profanity or links to inappropriate websites."

Other no-nos include job searching, doing work for another employer, looking at sexually explicit material and disparaging other employees via email and the Internet.

Bissot says that before sending an email or visiting a website at work, you should ask yourself whether you would feel comfortable if a co-worker walked in and saw your screen.

"That's always a good test, because if your heart is racing and you dash to that minimize button, you probably shouldn't do it in the office," Bissot says.

—Written by Kristin Colella for MainStreet