I know the answer is probably really obvious, but, what is "ping"? Thanks

^ Thats a ping. It lets a user know someone replied to them. c: (Sorry if I pinged you multiple times, the arrow wouldn't work :c)

It sends an event to the user, calling their attention to a particular post in a thread. You just use a @ symbol in front of their username, like I did with yours.

oooooooh! Thank youuuuu C: