An 'internet melt' is referred to someone who is really stupid/cringy on the internet this phrase is commonly used by youtube star Joe Weller who used to make videos exposing stupid people on the internet.
'your an internet melt!'
A person who obsessivly posts things/selfies on social media or acts like a roadman/rebel over the Internet.
Guy 1: Ugh have you seen Olivia's account recently?
Guy 2: Yes she posts way too much, her selfies aren't even that nice
Guy 1: The internet melt