How to download a copy of everything Google knows about you
Google allows its users to download a copy of everything they have stored on the company's services, including Drive, Calendar, Gmail and Hangouts. You can download your own archive of this information from Google if you want to create a backup before deleting your Google account and moving to another service.
How to download a copy of Facebook data about you
Facebook keeps a treasure trove of information on you, which goes all the way back to when you first started to use the social network. You can download your own archive of this information if you want to see what Facebook knows, or if you want to leave the social network and take your history with you.