As much as email, usenet irc and jabber/xmpp can be accessed over Http(s) - there are gateways.
(xmpp might be a special case here - I'm uncertain of the underlying transport for jabber; could be that js+http(s) is enough to simulate actual jabber client?)
(xmpp might be a special case here - I'm uncertain of the underlying transport for jabber; could be that js+http(s) is enough to simulate actual jabber client?)