Millions of Americans use social media to connect with and keep friends and families up to date. In most cases that is a wonderful thing… but your posts can also be used in a less positive way. For example, many debt collection agencies now use social media to get information about a debtor's address, employer, or recent activities. If you set your social media profiles to allow anyone to see your information or posts, what you provide can be used against you.
In fact, what you consider to be harmless could be risky behavior. Say you announce you're about to leave on vacation criminals could access that post and realize that your home will be unoccupied for days.
In short: If you aren't willing to tell everyone something, don't post about it or make sure your posts are only accessible to people you trust.