Avahi (Zeroconf) on Linux: What is it Good For? - page 2
Bonjour, M. Zeroconf, What Do You Do?You can also set up your machine to appear on your local network as machinename.local (can be useful for a home network if you haven't got proper local DNS running; I certainly don't and usually rely on setting options in ~/.ssh/config so I don't have to remember IP addresses). Copy the sample service file in /usr/share/doc/avahi-daemon/examples/ssh.service to /etc/avahi/services/ and restart the avahi daemon. Then run avahi-browse-domains -a -t (from the avahi-utils package), and you'll see your machine listed as running an SSH service. To browse all available services, use avahi-browse -a -r -t (-a shows all services, -r resolves the details of the services, and -t terminates once it has a full list).
Similarly, whilst CUPS handles printer setup, avahi should in theory at least make it easier to set a printer up as remote (by setting the printer up in avahi on the machine to which it's connected). Currently, however, this seems to be problematic: you'll need to write your own ipp.service file and add it to the /etc/avahi/services/ directory. The avahi.services (5) man page is comprehensive, but unfortunately there's no example file in the package for printers (just for ssh, as above). I wasn't able to test this directly, being a dead-tree-free operation! It may be more useful if you're running Macs on your network: Bonjour should autodetect the printer once it is shared. There are also other possibilities: remote desktop sharing, for example, and document sharing.
So, yes, there are uses for avahi, but it seems like it's still -- in terms of the user experience, anyway -- a project which needs more work. I can understand if it is the case that Debian/Ubuntu are making it a default install in order to encourage more user software. I'd certainly like to see more use made of this. It has the scope to be much more useful (especially for those who are lazy, or running Mac/Linux networks) than it is now; hopefully that will develop further in the near future.