A button at the end of each post that gives the ability to send any amount of SBD or Steem to the author. For those times when you stumble upon such a good piece of content that you feel an upvote and a resteem simply isn't enough. :)
I know that we have the option to go to the wallet and make a transfer to the author if we so feel inclined, but a tipping button would make this option more user friendly. It would contribute to more liquidity on the platform. It would probably be used most by dolphins.