what is this @ crap on a forum? DUMB
Oops,at first it didn't click as to what Ghost was referring to.
As Serfaina explained, it's a way of mentioning another forum member when posting. But I do get where Ghost is coming from - most of us use forums to get away from the scourge of social media and the forms of address they use.
Clearly this isn't social media, but handles are handy when mentioning someone else. It's not compulsory either.