If you use social networks and webmail to conduct business, and share videos, photos, stories and events, you are storing a lot of information on these companies’ servers. In the event that something goes wrong with the site, you could potentially lose all of your information forever. To prevent this, many
companies have introduced services to back up your information on social networks. When choosing a service, look for those that allow you to back up your information on your local hard drive. One such service is SocialSafe, an Adobe Air application with an easy-to-use interface that allows you to save all your content from your social network account directly to your local hard drive.

See
also, How do I keep my personal information private among my friends on social networking sites?