I've never read Homestuck but there's a type of media that I call "a Homestuck" and I think it's a useful categorization. The main criteria are:
long enough that the time investment is a serious barrier to entry
irrevocably changes your personality
brings something genuinely unique to the table. there is no real substitute for reading/playing/watching it in its entirety
Fate/Stay Night is a Homestuck. Worm is a Homestuck. When They Cry is a Homestuck.
Undertale has cultural impact similar to a Homestuck at first glance, but the fact that it's a pretty short and accessible game means that you don't get the particular mix of sunk cost fallacy and an intimate experience with a piece of media that results in you needing to connect with others who have already put in the time investment. You can buy your friends Undertale and expect them to play it if they're not too busy; telling a friend to read Homestuck is giving them a quest that, if accepted, will spark an odyssey. to read someone's Homestuck is an act of love without true equivalent.
