Fun bit of information: Utopia (Utah's fiber+wireless broadband network) is 100% Ethernet. Which leads to some really interesting circumstances. During a period there was construction somewhere upstream of me, my internet got cut a couple of times. It would always fairly quickly come back, but sometimes my IP would change, as would my promised speeds. Investigating why it was slow once, I discovered that I had a Comcast IP address. Called up the support and asked what was going on, and we eventually tracked it down: Someone had bridged a Comcast business network and Utopia connected network somewhere, and when my router couldn't get DHCP from the ISP, it grabbed one from this Comcast network, and happily sent my traffic through their network. Got that fixed pretty quickly.