Karezi: Moirails?

Like i said, obsessed with homestuck. this came right before the flash when karkat and terezi are trolling, and after they stop talking, karkat goes back on and types '<3'. WHAT DOES IT MEEEEEEEEAAAAAAAN? The troll universe has this very complicated romance procedure, where up until now the author had them in the 'friendship' phase. but I think they go pretty well together.