Is there someone you don't like on the server that you want dead? Enjoy doing mercenary work? You can now fulfill these desires with the new Bounty System!
Simply do /bounties ingame and you will be shown the bounties GUI. Here you can see the current bounties available. Hover over a head to see the name of the person, the amount of money you can claim the bounty for, and the number of players currently tracking the player. To take a bounty, click the head of the one you want in the gui. This will add you to the number of players tracking them.
If you would like to create a bounty, do /bounty <player> <money>. This will add that player to the listing.