Post the wrong thing on social media and you can lose your job. It may seem unfair, but some companies view their employees as an extension of their brand, and you don't have to do something over-the-top to get into serious professional trouble.

There have been multiple recent examples at ESPN, for example, where high-profile current and former employees have been suspended for social media posts. But it's not only famous people or those in public-facing jobs that have to worry about this. If you have a job or hope to get one someday, you have to at least consider that your employer may monitor what you post.

Protecting yourself, however, isn't that hard. You mostly have to understand what the rules are and use a lot of common sense.

People type on laptops tablets and phones.

What you post on social media can impact your career. Image source: Getty Images.

Know your company's policy

Many companies have an official social media policy. In a broad sense, this will lay out rules for what employees can and can't do. The parameters will often be quite wide, but this type of document at least establishes some basic boundaries.

For example, if the policy outlaws using "hate speech," but does not define it, that's only helpful to a point. Still, even having some basic idea of what your company won't tolerate should help you with the second rule to keep social media from ruining your career.

Assume a wide audience

When I post on social media, I know my mother is going to read it. That has perhaps stopped me from making certain bawdy jokes, and it has perhaps caused me to pull back on other comments.

When you post on social media, you should assume that not only will your boss read it, but so will your grandmother, some of your elementary school teachers, and probably that woman on The Simpsons who says "I never" before passing out in offense.

Know your permissions

All social media sites have privacy settings. In general, it's best to assume that even private posts are public, but you should still make sure you've set up your permissions and understand who is supposed to see your posts.

Again, never post anything you would not want your company to see. You never know how something will be shared or where it may end up. Still, privacy settings are useful because your work contacts may not be interested in your personal posts, and you can in theory control who sees what.

Avoid the obvious fails

There are very few employers who want to see risque pictures of their employees, and many consider sharing them to be appropriate behavior. The same is true when it comes to any sort of foul language or images of you (or your friends) after a few too many adult beverages.

Be careful with politics and religion

Your employer can't fire you for your political or religious beliefs. That does not mean you should be reckless about sharing them online. This is a very grey area where you should be careful and understand who you work for.

While laws may protect you from being fired for political or religious views, they can't shield you from a crafty employer. If you worship house cats and support eliminating driver's licenses, to use some silly examples, that may change how your church-going, dog-owning, pro-regulation boss feels about you.

That could put you on the chopping block if layoffs are needed, or stop you from getting a promotion. Some social media has become very political -- but realize that sharing any view may change how someone else (notably your employer) feels about you.

Always be positive

A final rule for social media is that it's best to avoid the negativity that has become common on Twitter, Facebook, and, to a lesser extent, other services. It's probably OK to be negative about a movie or a new fast food item, but in general focus your digital presence on positive things.

Sharing pictures of your meal or saying how much you enjoyed Hamilton may be boring, but they probably won't get you in trouble at work. Make your social media about sharing good news with friends, family, and, knowingly or unknowingly, your boss.

Have fun on social media, but remember that it's essentially a public place. Don't post anything you would not want to be seen by a wide audience.

Daniel B. Kline owns shares of Facebook. The Motley Fool owns shares of and recommends Facebook and Twitter. The Motley Fool has a disclosure policy.