Act 4 - Internet Trolls
Panel of Karkat Vantas in his room
As a webcomic, Homestuck is largely shaped by internet culture. It's interesting to see happen while reading, the shift in tone and the style of jokes made as the comic (and the internet) develop over 7 years.
Very notably, the Homestuck species Trolls, are based off of actual internet trolls and some characters existing as parodies of other characters in popular media or as tropes.
Terezi starts as a parody of Two Face from the Batman comics. Shes obsessed with law, justice, constantly flips a coin to make decisions (head/bad heads). Gamzee is a parody of juggalos, fans of the band Insane Clown Posse. Karkat is perpetually angry and shouting, most similar to the internet troll stereotype (Which makes sense as he is one of the most important trolls and the first one we meet in Homestuck). Nepeta is representative of shippers in fandom, she literally has shipping charts painted across the walls of her home.
Terezi flipping her coin
Other examples include:
Kankri-Tumblr SJWs (Social Justice Warrior)
Cronus-Greaser
Meulin-fandom bloggers
Porrim-Alt Feminist bloggers
Latula-Sk8er Gamer Girl
Eridan-Incel Culture
Beta Trolls