I Don't Know Yet.
Instead of saying
IDK (I don't know) to a question, you can say IDKY so your
friends at least have some reassurance that you'
re going to make the effort to answer the question in the future.
Sam: "Hey
Tommy, are we on tonight?"
Tommy: "IDKY" (This most likely means that
Tommy will eventually tell Sam whether or not they're going to hang out. In this case, Sam has the reassurance that he should get the update at some point that day.)