Adding Authorized Users to get more miles
 

I'm curious to know which cards provide a bonus for adding authorized users/additional cardholders to an account. It seems there ought to be a Master Thread for the most up to date information on this question.

I know that earlier this year, BA had a promotion where people could get 5,000 points for adding cardholders to the account.

Amex also infuriated a bunch of people by accepting fees to add users then refusing to award the promotional points since the deal was supposedly only applicable to residents of Argentina.

I know I have seen several sign-up bonuses that increase the bonus if an applicant adds authorized users (though, I can't remember any of them right now).

Also, if you track your credit score closely enough to know how adding an authorized user impacts the added person's credit score, please share.