We’ve all been there. Scanning one of your social media profiles, you notice a photo posted by a respected colleague in a less-than-professional situation. Maybe you cringed a bit, knowing the photo didn’t match the professional persona you know your colleague wants to convey.

Increasingly, as personal and professional lives become more enmeshed, even talented professionals run the risk of getting fired or not getting a new position because of what they post on social networks.

Laws in different countries are still evolving in terms of what employers can and cannot do with what they find via social media sites. But it is not uncommon for both candidates and employees, especially in the United States, to be asked to hand over their personal passwords so supervisors or human resources can access their profiles. A recent ruling in the US protected some speech on social networks from retaliation by employers, but it doesn’t cover everything.

Even so, there is little doubt — whether found accidentally or purposefully — that what you post online can impact your career. One in 10 job seekers between the ages of 16 and 34 have been rejected for a job because of something posted on their profiles, according to a recent survey from London-based mobile research firm On Device Research. That figure is expected to grow. Two-thirds of the 6,000 jobseekers in the US, the United Kingdom, China, Nigeria, Brazil and India who were polled for the survey said that they were not concerned that their current use of social media could harm their career prospects.

But now more than ever, it is important for the career-minded to retain tight control over their social media profiles.

What is acceptable?

What passes for acceptable to one person may not be to others who scan a profile. While most people realize a professional network like LinkedIn is not the right place to post about a wild party, not everyone recognizes the danger of doing so on sites like Facebook or Habbo.

“Whether it’s their views about religion and politics to personal feelings, some people don’t understand what’s appropriate and inappropriate to post on social media,” said Heather R Huhman, founder and president of Washington, DC-based consulting firm Come Recommended.

One gauge: ask yourself if you would want your grandmother to see the information, said Kathleen Brady, a New York City-based career management coach and author of GET A JOB! 10 Steps to Career Success. If not, refrain from posting.

Complaining about a boss or your job on any social media website is almost always a mistake. Many people think their employer will never see such posts, but you never know when someone will forward something you have posted or simply repost it elsewhere. Such behaviour on Twitter or Facebook could end up costing you a job, said Huhman.

Among the casualties: recently, a Taco Bell employee in California was fired after a photo of him licking a stack of taco shells made its way to the company’s official Facebook page. And a government employee in New Zealand was fired a few years ago after a Facebook posting about her role as a “very expensive paperweight” and described the time she wasted and stationary she stole from the office. Even social media editors are not immune — a Bloomberg social media editor lost his job this spring after a Twitter contact shared a private direct message he had sent about frustrations at work.

Some social media networks allow you to have separate profiles for your personal friends and family and a more professional page for acquaintances and anyone browsing the web looking for information about you. But this is no guarantee that inappropriate posts or photos from your personal page won’t be shared by someone with more lax privacy settings.

If you do find out that racy photos of you or your negative comments about your boss ended up being shared, you should try to delete them. Remember, though, that content on the Internet rarely disappears for good and the wrong person may have already seen it.

“No excuse can cover up one of those mistakes,” Huhman said. You’re much better off admitting the mistake and letting your boss know that it won’t happen again, she said.

The right way

Being found on social media is important to building a career, establishing a presence as an expert in your field and keeping in touch. But sharing too much personal information online is always a mistake. Over-posting can be problematic, too, since it can make you appear unproductive. Having too little information in an online profile can be interpreted as trying to hide something or as a sign you aren’t well-established in a career or community. The key, say experts, is striking the right balance.

Establish yourself on a number of platforms, but make sure to maintain each of them appropriately. For more professional profiles, on LinkedIn or XING for example, you can simply post links to relevant articles to create a presence for yourself or join discussion groups and participate — professionally — in conversations that apply to your line of work or expertise. Keep in mind, your comments on articles and blog posts can often be found in search engines. So be careful what you type when commenting.

You can also draw attention to your more professional profiles by being selective about where you post, said Dan Schawbel, author of the upcoming book Promote Yourself: The New Rules for Career Success. Do you really need a profile on Facebook, MySpace and Google+ to keep up with friends and one on LinkedIn to keep up with your career? Consider culling the number of profiles you maintain.

Take advantage of tools like Hootsuite.com and SproutSocial.com, which allow you to manage all of your profiles from one place, suggested Schawbel. That way, you can be sure to maintain consistency in how you present yourself — or in how you selectively present personal information. Make a spreadsheet of the social networks you're on and mark the date when you update each profile so you can ensure they are consistent and current.

And don’t forget to Google yourself regularly. A 2012 survey from Connecticut-based ExecuNet found that 90% of recruiters type candidates’ names into search engines to get more information about them than what is on their resume.

If they’re doing it, so should you.