There are time when I ask a question and receive multiple answers. There have been many cases where the answers provided are outstanding and I would like to give credit to multiple answers with more than an up vote.
For instance I accept the best answer as my accepted answer. But I also have the option of marking another answer as a great answer or with some sort of acknowledgment. When awarded you receive +10 reputation vs the +15 of an answer and you are limited in how many you can award. (Say no more than 2 per question or possibly even 1).
This lets other users know "This answer has merit as well as the accepted answer."
As far as I am aware no other SE site does this yet it would be nice to see implemented.