I don't know the code that everyone uses in a comment in a forum that alerts the user they are replying to. IE:

Help plz?

That's what I get for not going on Subeta in months ._.

Lol, you just did it. :P Just put the at sign before their username, and tadaaa! :D

Oh. Wowwww. Thank you!

Jeeez. Hahahah. "Here's your sign..."