For years, people have been able to spend their hard-earned imaginary Internet points to add "bounties" to questions in order to attract more attention to them.

But does this actually work?

Do questions that have bounties get more/better answers (in aggregate) than questions that never had a bounty? Does this vary by site? If so, do bounties seem more effective at a certain site "size"?

Or is it really just a wash, and we're getting no extra value for those points we're spending?

For years, people have been able to spend their hard-earned imaginary Internet points to add "bounties" to questions in order to attract more attention to them. (Because, really, "attention" is the only thing that you can be reasonably sure a bounty will give you.)

But does this extra attention translate into better results?

Granted, any individual question may not be really answerable or is still boring even with the extra carrot. And a question might be so interesting that it would have gotten a ton of (good) answers even without the bounty.

Do questions that have bounties get more/better answers—in aggregate—than questions that never had a bounty? Does this vary by site? If so, do bounties seem more effective at a certain site "size"?

Or is it really just a wash, and that all anyone ever gets for their bounty is extra attention?