@Aurorastar, for the record, this is adapted from a web novel and while the manhwa itself leaves the year ambiguous, the web novel is specifically set in 2010. The manhwa has them using smartphones and the like to keep with the times, but in the original web novel, they were still using flip phones. So if the logic behind the username feels anachronistic, it's because the manhwa's adapting a story that's set a decade ago. But honestly, I don't know what's not to get about the username thing. It doesn't even have to be generated by the service when you're signing up for an account. Maybe some people just like to use an easy set of numbers to remember so they pick their birthday? It's not rocket science.
But the whole point is that the intent behind the username was obviously to frame Dani so of course it's going to be something blatantly damning
at first glance, along with all the snippets the person has posted that make it clear it's someone who hangs out with Yeoryeong. Everything about it is made to lead back to Dani.
What's dumb is that the perpetrator thinks any decently intelligent person would use such an obvious username to post hateful messages about a person they're supposedly friends with. Because Dani would definitely talk shit about Yeoryeong online with a handle that has her last name and the three digits of her birthdate and not expect to get caught, huh?