Delete stolen contacts in social networks

How to delete stolen contact lists - address books - from LinkedIn, Facebook, and Twitter.

I was long aware that all the big social networks had stolen your contacts when you installed their apps on your phone. What I didn't know, is how to delete them, but for my surprise, there seem to be easy ways to do this. I'm not fooled: they are most probably just archived, but this is better, than nothing.

Facebook
Manage Invites and Imported Contacts1
LinkedIn
Imported contacts2
Twitter
Manage your contacts3

This really, really should only be allowed as opt-in, not as default.

(Oh, by the way: this entry was written by Peter Molnar, and originally posted on petermolnar dot net.)