I've never participated in this before, but it sounds like so much fun! R.A.K is a feature hosted by Book Soulmates. Participants post their wishlists from Amazon, B&N, Goodreads, etc. to the Google doc on their page. This allows other participants to see their wishlist and possibly buy something from it for you! It also allows for you to see others' wishlist so you can do a random act of kindness for them as well.
I think this is a great idea! It allows us all to help each other out and do something nice for someone else. If you would like to take a look at my wishlist, it's located HERE.