enabled -- default false.
dnsApiServer -- the server we call to allocate host names.
cname -- the canonical name for this server.
domain -- the domain we allocate from.
Obviously, nothing happens if enabled is false.
If it's true, when a new user is created, his domain attribute is set as follows. We take his username, and combine it with the domain, to form the domain. So if the domain pref is "worldoutline.org" and the user's name is "fred" -- it will be fred.worldoutline.org.
We call the indicated dnsApiServer to do the allocation. The format of the server spec is the same as the format used in the editor. xmlrpc://foo.myname.com/RPC2