How to remove your Social Number account
Be logged in. Right top, hold your mouse pointer over your username (number). Click Account Settings. At the bottom of the page there is a link: Cancel Account. Use it. Another good part: all info of/about you will be erased. Well done Social Number.
Direct removal link: http://socialnumber.com/user/
Helpful Trick: Removing online data
Helpful Trick: Remove third-party logins
If you signed up for Social Number using a third-party login such as Facebook or Twitter, you probably want to revoke all access from Social Number. Click here to find out how.