Hey @blmahon!
I've never had a reason to use the IS_SAME() function, but I think today is that day!
Give this formula a shot:
IF(
IS_SAME({Date to Post}, TODAY(), "day"),
"Post"
)
Here's the behavior it returned me when I tested it:
As a side note, it might not be totally relevant or applicable to your use case, but your post reminded me about this thread from yesterday. Might be worth a look to see if it might support or influence your solution a bit.