Paid Registrations Tip other members posts to micro-gift account upgrade

I would like to suggest a Tip function, where users can reward other users for good content by Tipping them a small amount. This function is a form of gifting account upgrades, but multiple tips are needed for an account upgrade to be attributed to the receiving member.

Reddit and other sites have various TipBots to reward members. It can work very well to drive content creation. Similar functionality has frequently been sought after by xf admins. I suggest a simple function:
  1. Each post would have an icon for tipping.
  2. Members can buy tipping credit. For example they could buy $10 tipping credit.
  3. When the icon is clicked the user gifts the author a set amount. For example $0.10. (amount is set by admin) This is added to the authors account and subtracted from the readers account.
  4. When the author has received enough gifts for an account upgrade, the author is notified with an alert that they can activate the account upgrade.
  5. When activated, the account upgrade is added to their account.