I set up a bounty on another person's question and awarded the same within 7 days, and received my
Altruist badges a couple of days back. The badges were awarded retrospectively - the bounty was created and awarded a couple of days before the badges were implemented.
Just now SO surprised me saying that I received a
Benefactor badge for the same question. I thought the
Benefactor was for awarding bounties on my own questions. I've never started a bounty on any of my questions let alone award them.
I guess it's a bug. For what it's worth, I got my
Electorate badge (my first golden one) along with it. They came together; it said - "you've earned a Benefactor and one more badge: check your profile"
My question is, how do I exploit this bug to get a Gold or at least a Silver badge ;)