[andrewtj]

I'm not sure this is the "best feature" that no one uses, but it is one that I've always thought some crafty hacker could do something cool with.

BonjourFoxy[1] adds Bonjour support to Firefox and is predominately used to find websites advertised by printers, network cameras and so on, but it can also be used by other extensions to advertise and discover network services.

Currently the only extension I'm aware of that makes use of this is iGiro[2] which combined with an iPhone app let's you scan bill numbers straight into Firefox's text field.

Now admittedly I haven't got any killer P2P extensions in mind, but surely some other folks out there do —?

[1] http://www.bonjourfoxy.net/

[2] http://igiroapp.se/