How much personal information should you give away online?

zero

NONE

not much most of my profiles are fake names and cartoon pics

the ones that have my names and pics are all private

yes.

Social Media: As little as possible. Don't give out your last name & no contact phone numbers or physical addresses. Don't even hint at this. Stalkers use the small details to put together information & track you down.
Social Media for Business: Give as much details about the business but little to no information about yourself. No pictures of yourself.
Online application forms: only if the website has a privacy policy should you divulge personal details. If these applications need your banking details, check that the website uses extra security measures to carry out transactions safely.

nothing