When we discuss some topic here with other posters, you have limited information about them. You often don't know their real name, their age etc. etc. According to the MWI, this then means that the other people you are talking to exist as a superposition of all possible real persons. E.g., there exist worlds in which I have a beard and there are worlds in which I don't have a beard. Everyone at PF except me has an exact copy in both worlds.