"Real time" communication, like a chat, or even voice, is good, but for a site that reaches people in all 24 time zones, not very user-friendly, as it would require users to be up at odd hours if everyone is to participate.
Someone could write the most eloquent poetry, but in a chat, it is lost forever quickly in the crowd of age-sex checks...
Anything worth keeping is quickly lost in chat, but is available continuously in a forum like this, other people can add to it, comment on it, search for it, catalogue it, etc... it is always there.