When you look in the mirror, do you see the same image that your co-worker or boss see when they look at you?

If you're not, you may be in trouble.

That's because your reputation is critical to your career success, and if your self-perception is out of sync with what others believe, it can not only hold you back now but forever hinder your progress.

Marshall Goldsmith, a leadership guru, says that many people are clueless about their reputation among business associates. For example, you may be unaware how your behavior — including in your private life — impacts how others feel about you. You may think your education and work history mean your professional reputation is great — but colleagues have been passing around photos of you drunk at a party, or the blog post you wrote about trouble in your marriage.

Goldsmith says one of the biggest blows to a career reputation can be made online, especially through social media sites such as Twitter and Facebook. "People post about their private lives on these sites, where anyone can see them. It's insane. They're showing a total lack of judgment," Goldsmith says. "It takes about two minutes to find something out."

At the same time, monitoring your reputation can be critical if lies are being spread about you — your career can be torpedoed if you're not managing information and aware of how others see you, he says. With the Internet, and "everyone having a camera," it can be tough to maintain control over your reputation, but the key is being vigilant about not letting your private life overlap into your professional world.

While what you say on Twitter or Facebook may not seem like a big deal now, will it still be OK if you were suddenly out of work and needed to apply for a job? Or, if you were up for a big promotion? How would a boss or potential employer view your words and actions?

"The truth is, we may never completely know how a damaged reputation impacts us," Goldsmith says. "It can be a silent career killer. That's why it's time to quit drifting through life, and understand the importance of being aware about what is being said about you."

As for the contention that many people believe being "transparent" online is a way of just being themselves, Goldsmith says that instead of "revealing honesty," such actions show a lack of professional judgment that will haunt the person for years to come. "It comes down to this: Your personal life is personal. Keep it that way," he says.