That is correct. And no, people don't use jump links everywhere--only if their site is new and they are passing the links to folks on IRC, etc.
Another thing I forgot to mention: if a name is unknown, your local HTTP proxy will ask you if you want to try to lookup the name from one of several popular "jump services", which are the same services providing address book subscriptions. This is where jump links come from most of the time.
Another thing I forgot to mention: if a name is unknown, your local HTTP proxy will ask you if you want to try to lookup the name from one of several popular "jump services", which are the same services providing address book subscriptions. This is where jump links come from most of the time.