It does not appear to be a message from Karkat directed at you specifically.
He has just updated one of the many memos on the transtimeline bulletin board he set up a while ago. You've since no longer bothered keeping up with the endless and mostly incomprehensible communique.
But while checking the update, you can't help but skim through the first memo in the long sequence, which was written hours ago from your present perspective.
Hey check it out. Every week we'll be revealing some new troll characters from Hiveswap until Act 2 is out. Follow the Troll Call here, and meet the first two here. Expect a few more surprises like this to drop in coming weeks.