In case you are worried about Bonjour sending advertisements onto the local network because it compromises your privacy or because you are worried about security, know that you can disable them. It is described in http://support.apple.com/kb/HT3789:

$ cd /System/Library/LaunchDaemons
$ sudo vi com.apple.mDNSResponder.plist

and replace:

        <array>
                <string>/usr/sbin/mDNSResponder</string>
                <string>-launchd</string>
        </array>

with

        <array>
                <string>/usr/sbin/mDNSResponder</string>
                <string>-launchd</string>
                <string>-NoMulticastAdvertisements</string>
        </array>