For those times when someone tells you about an event (including the time and place) with the intention of you attending, but doesn't explicitly invite you. For example:
A: "A bunch of us are going out to Pizza House for drinks/food after our outdoor game tonight. Jacki and Brandon will be there so you'll know them. Our game ends at 8 pm so we'd be to Pizza House around 8:30 pm."
B: "Thanks for the implivite!"
A's statement implies an invitation to B, but there is no actual, "Hey you wanna join" or "You should come!"