Internet Slang: "lol" or "xD" ?

In the past few days i've noticed something different about the gaming chats i go on and the random chats from IMVU i go on. They seem to have different "dialects" if you will. For example: I say something funny in the IMVU chat, and all i get is an lol. Nothing more than lol, every single time. When i say something funny on the gaming chats, *cough http://www.xat.com/GFvNS cough* i get all sorts of messages like "xD" or "roflmao" or something. Another thing i've noticed in the differences in these dialects--now referred to by me as "Casual internet slang" and "Hardcore nerd slang"--is that in the nerd slang, you get a lot of exaggeration of the lols. In the casual slang, the only time you'll get the slightest LOL is if you actually make them lol, whereas in the nerd slang, you say something the tiniest bit funny, and people say lol. You say something that has people laughing out loud, they say rofl. If you have people rolling on the floor laughing, i don't really know what they would say, as they would probably be too preoccupied with rofling.