If you're a member of either the professional social media site LinkedIn or the dating site eHarmony, your account could potentially be in danger.

LinkedIn and eHarmony have both confirmed that a number of passwords from both sites have been stolen and leaked on to the internet.

Business social network LinkedIn and online dating service eHarmony said Wednesday that some of their users' passwords were stolen and millions appear to have been leaked onto the Internet.LinkedIn Corp. did not say how many of the more than six million passwords that were distributed online corresponded to LinkedIn accounts. In a blog post Wednesday, the company said it was continuing to investigate.

Graham Cluley, a consultant with U.K. Web security company Sophos, recommended that LinkedIn users change their passwords immediately.

LinkedIn has a lot of information on its more than 160 million members, including potentially confidential information related to jobs being sought. Companies, recruiting services and others have accounts alongside individuals who post resumes and other professional information.

Currently, it is unknown who the culprit behind these attacks is, or the exact number of passwords that were stolen. The accounts who were affected by the attack have had their passwords reset, but the damage may already be done.

It's cases like this that reinstate the importance of being smart with your passwords. To keep your accounts safe, regardless of what site you're on, I would recommend changing your password periodically, about every few months or so. Also, don't use the same password for multiple sites.

For tips on how to create strong, secure passwords, check out the Geek Girl Report.