This somewhat more fancy implementation of that idea is used on many German websites: https://github.com/heiseonline/shariff https://github.com/heiseonline/shar

This somewhat more fancy implementation of that idea is used on many German websites: https://github.com/heiseonline/shariff https://github.com/heiseonline/shariff or https://github.com/panzi/SocialSharePrivacy https://github.com/panzi/SocialSharePrivacy