Added to the end of wriiten insults (most likely graffiti) to say that even if it is removed, then the fact remains that the insult is true. Usually based around truth.
Well, you know it's true!
"Miss High Maintenance is dating a gamer. I don't see that working out."
Put on the end of messages by immature schoolchildren so that if a message is destroyed, it's appatrently still true- regardless of wether or not it was true in the first place.
Can easily be counteracted by destroying the IDST first, removing it's protection, then removing said message.