It seems as though everyone has an account on at least one social networking site these days. You're all familiar with them - Facebook, Twitter, LinkedIn, Instagram, Foursquare, etc. These sites, along with posting to any website, come with some security risks.
Be sure to read the privacy policies of any site to which you post.
Most social networking sites have privacy policies to which you must agree before your account is created. These policies state what protections you are offered for your information. You should be sure that the sites to which you post have policies that protect your information and your identity.
Don't post anything you might regret.
Information posted to websites is not deleted from the Internet when you remove it from the site. There are many websites and companies archiving the contents of the web for various purposes. You should only post information, including pictures, that you don't mind other people, including the general public, seeing.
Many companies and colleges have people searching through social networking sites to look at applicants. People have been denied jobs because of information or pictures that have been posted to their Facebook or Twitter accounts. This goes along the lines of "don't post anything you wouldn't want your grandmother to see".
Be careful about publishing personal information.
Personal information, such as phone numbers and addresses, should be left off social networking sites. Believe it or not, people use these sites to cause harm. Stalkers use addresses and phone numbers to stalk their victims. Use security settings to restrict who can view various information about you on these sites, but keep in mind that security can be breached.