I've been using these records with XMPP servers for some time now and it works quite well. An added benefit is that you can run services on non-standard ports a

I've been using these records with XMPP servers for some time now and it works quite well. An added benefit is that you can run services on non-standard ports and make this information available via DNS. Of course if the web supported this, it might make it fun for people stuck behind firewalls/proxies run by administrators who think it's a port 80 world out there. In the case of Jabber/XMPP it seems to be universally supported by servers now. Most clients should support it as well. Both are required to support it to be XMPP (RFC 6120/6121) compliant, possibly because there was no standard privileged port that could be allocated.