If you are trying to optimise your OSX system and want to shut down services that you are not using, Bonjour might be one to target.

You can disable Bonjour with the following commands:

sudo launchctl unload -w /System/Library/LaunchDaemons/com.apple.mDNSResponder.plist
sudo launchctl unload -w /System/Library/LaunchDaemons/com.apple.mDNSResponderHelper.plist

You can then re-enable it with the following:

sudo launchctl load -w /System/Library/LaunchDaemons/com.apple.mDNSResponder.plist
sudo launchctl load -w /System/Library/LaunchDaemons/com.apple.mDNSResponderHelper.plist

You could test to see if the services are running using ps:

ps aux | grep mDNS

Or you could use launchctl:

sudo launchctl list | grep mDNS