@lienminh247 has set 3.000 SBD bounty on this post!
What is a bounty exactly?

A bounty is money sent to a post to be distributed to the users commenting on it. It provides a way to reward users directly and works in addition to the steem/sbd they receive from the blockchain. It works independently of SteemPower.

You create a bounty by sending any amount of sbd/steem to @steem-bounty together with a post-url in the memo.

How can I earn a bounty Users are then competing for the bounty by writing their answers to the post in comments that will achieve upvotes from the community and especially the bounty creator. The money of the bounty gets distributed to all top level comments of the post at the same time when the post is paid out (7 Days after it was written). How much everyone gets depends on the votes the comments received. The sender of the bounties votes are weighted higher so that she decideds where 80% of the bounty money goes and all other votes determine the rest.

@steem-bounty does all of this for you automatically. You can use this service to automatically pay out a challenge, ask a hard question or simply to reward the people that interact with you.

Read more about how it works, even in different languages here.