How much of your information is online?
When you use your phone to sign up for apps, and share your social media information, you give permission to third party companies to access and share your information. Companies like facebook, twitter, and other social media companies, let third parties access their data base for marketing purposes and access your information.
Whats at risk. You share your photos, address, email, phone number, education, or whatever else it is you post online. All of that information will find its way to search engines and be shared and viewable by anyone who searches for you.
How is this possible? It is possible since people are voluntarily sharing their information online. We voluntarily share our photos, locations, achievements and whatever it is we can share. Humans are social beings, and we love to share our information however we can!
If you would like to get your information removed (since its public information, and you agreed to terms and conditions), you will find it to be very hard.
You can revoke third party access in all social applications or any websites/applications you sign up to. Read terms and conditions and understand what you are getting into before you sign up. The process is long, but is doable. If you do not care about your information being out there, and you are fine with it; then you have nothing to worry about!