Every now and then, you may notice that a Facebook friend's status updates have turned ominous. The messages instruct you to copy and paste a certain phrase into a post on your own wall or risk that your content may be hijacked by Facebook. Here are three recent myths that, with the help of Snopes.com, have been proven false.

1. Facebook Privacy Notice
Variations of this one seem to crop up every few months, and many intelligent people fall for it. It says something like: "As of [date] at [time a.m./p.m., time zone], I do not give Facebook or any associated entities permission to use my pictures, information or posts, both past and future. By this statement, I give notice to Facebook it is forbidden to disclose, copy, distribute or take any other action against me… The content of this profile is private and confidential information. The violation of privacy can be punished by law. All members must post a note like this. If you do not publish a statement at least once it will be tactically allowing the use of your photos, as well as the information contained in the profile status updates."

According to Snopes, this myth has made the rounds online for more than a year. While it's true that anything you post online may live on forever, Facebook does not own your content. Your use of Facebook does, however, give Facebook a non-exclusive, royalty-free license to use any content you post that's covered by intellectual property rights (such as photos or video) without having to pay you for it. You may limit these rights by controlling the privacy and app settings on your account (check out Facbook's legal terms here.)

Facebook's terms of service are essentially a "take it or leave it" contract – you either accept the terms or don't create an account. In other words, you can't singlehandedly modify the terms of a contract by simply posting a statement without the other party's consent.

So although this one's a myth, it's not a bad idea to review the terms of service and privacy policies that govern your use of social media platforms (and adjust your privacy settings), which can change at any time.

Related: 7 Biggest Myths Business Owners Believe About Using Copyrighted Material

2. Your private posts will show up in public search.
This myth feeds on peoples' fear that their private information is being blasted across the internet and is visible to strangers, and crops up when Facebook unveils changes to the site. It looks like this: Users are encouraged to take action on their friends' individual profiles or risk deletion for posting private information. This is false. Facebook provides tips for those who wish to control who sees their profile via their privacy settings, and suggests reviewing and/or removing tags for photos in which you appear that others may have uploaded.

3. Giraffe photo virus.
You may have noticed your friends’ profile pictures replaced by photos of cute giraffes recently. Initially, the ruse was circulated as a riddle and, if the person didn't guess correctly, they were supposed to replace their photo with a picture of a giraffe. Then, word spread that the giraffe photos were infected with a virus that would enable hackers to control your computer or damage your smart phone. Snopes.com and other urban myth-busters put that rumor to rest quickly, noting the hoax was based on a 2004 warning about JPEG images linked to a malicious code, which was fixed by Microsoft nine years ago.

For more, check out Facebook's “common myths” page

Related: Facebook Facepalm: In Big Real-Estate Buy, Mark Zuckerberg Seeks Personal Privacy, Then Removes Online Privacy Feature