Digital Foot Print
You have one
You don't even know the half of it.
Every thing you do online can be seen by anyone. It can and will be held against you. All those times you thought "no one important will see this insulting post I made about my boss.", well your boss will hear about it one way or another, and when you go to apply at a new job after you loose your old one because of that post you new boss will go online to see what kind of employee you will be and you wont get your job. When you put something online, it stays there for everyone to see.
Think before you post
What you post can be used to bully you, insult you and hurt you. It can also go the other way, you could hurt someone else or even ruin a career. What you do online is being put out there for the whole world to see. You don't want anyone thinking bad about you, do you?