M2

you could get pedophiles that try and get in contact with you
people could hack your account and get your pin number and bank details and get into your bank account
they could read private messages to do with your job or something private
they could hack your account and change your password so you cant log in
you could get a spam letter and it could send a virus to your laptop/computer and make it become really slow or shut it down,
 could loose your work if the system crashes and you would have to re-do it.
 you can make this safe by;
making your password difficult and something that someone wont know
only have people you know on your site so it wont have pedophiles
dont let anyone on your site only yourself
dont answer spam
people could pinch your data
cyber bullying could take place
never put when your on holiday on facebook because people could burgle your house
always make a record of your password so you don't forget it