Let's say I asked an interesting question which got a lot of attention and some really good answers. My problem was solved because of those answers and I've accepted one of them. But I want to also pay some reward to the second best answer that already exists on my question. Could I start a bounty for that sole reason? Is it within the site rules?
Does question needs to stay in the featured area for 7 days?
If you’ve asked a good question, edited it with status and progress updates, and still are not receiving answers, you can draw attention to your question by placing a bounty on it
But I don't want to grab more attention on the question, I just want to award an existing answer
It has officially become a trend, There are three questions right now in the Featured section with reason
One or more of the answers is exemplary and worthy of an additional bounty.