In the early 2000’s it was popular among teenagers to have one’s own typing style along with signature emoticons. (We didn’t have emojis yet!) We used forums and simple chat rooms back then that either didn’t save a history or have been lost as the host companies purged their storage or shut down. Storage space for text and images used to be a lot bigger deal than it is today.

I think the person may also be referring to the “i can has cheeseburger” style that was very popular on cat pictures. It was like the more modern “heckin doggo” style.

You should read a webcomic called Homestuck if you haven’t already. One of my favorite things about it is how everyone in it expresses themselves in different ways. I will give you a content warning for slur usage though. It accurately reflects the way we spoke at the time. As the story went on through the years, we learned how our language and biases can be harmful, and the author addresses some of the previous bad behavior and language.