That may possibly be because you're constantly posting at least somewhere on the forum while you're online, or replying to or VM'ing someone at the time, so people will know you're just invisible xD Also, it still won't keep you from recieving VM's all the time you know :p But either way, you don't have to reply to people as soon as they VM you if you don't feel like it, but it's nice that you do ^^