I'm really excited about this idea. Remember the 90's when competition was fierce with dial-up ISPs? There was a huge factor that helped make that possible and it was commonly available lines to run the services over. Everyone had telephone lines and you could change your ISP simply by getting a new account and calling a different number. Each ISP didn't have to run an entirely new network to provide service to a population. They ordered a number of lines with telephone numbers, hooked up some modems and got a high-speed connection to the Internet and they were in business.
Dark fiber is so named because Fiber Optic cable carries data as light over its length. When it is "dark", that means there's no equipment hooked up to that line. If an area runs dark fiber to all of its homes and businesses, then they can in turn lease those lines to various companies who want to provide services over them. We can again have a ton of competition in Internet service without requiring each provider to run their own lines. Right now competition is very limited due to that simple fact. Here in Richmond Indiana choices are limited. Comcast provides cable modem service over their lines. Frontier and Parallax provides DSL service over telephone lines. Parallax has a limited roll-out of Fiber Optic as well. Then there's Bridgemax over a wifi-like wireless connection.
Internet service is not the only service that could run over Fiber Optic. TV providers and phone could also be run.
Why provide for competition instead of restricting it to a single provider? Not everyone will want the service from a single provider. That would slow down how fast a network could grow. It's not economical to roll it out to every house if only a few wants it. If the same network could be used for people who want service from Company A and people who want service from Company B then it can economically grow. Not to mention, with the added competition prices will go down while at the same time companies will also have to work on their customer service! It also opens the door for smaller companies to offer a service that would be simply impossible to offer if they have to build out their own infrastructure. The exceedingly high cost of building out infrastructure severely limits the possible competition.
Think of roads. Do we have Ford roads that only Fords are allowed to drive on? Do we have Chevrolet roads that only Chevys are allowed to drive on? No! So why not have a common infrastructure for all of our data services, such as Internet, Phone and TV?
Please note that I'm talking about Dark Fiber here. The service providers can bring their own equipment. If newer equipment comes out that is faster, then they can hook that up to the lines. Much like in the modem days when we went from 2400 baud to 56.6k. If Google offers service with 1Gbps equipment and newer equipment comes out that's faster, then they should be able to hook that up.
I've read an article recently about Google working with Huntsville Alabama to put this sort of idea into practice. It's not even the first place it's been tried and I'm very excited to see what happens. If Comcast & AT&T don't kill it off in court anyways. You can read the article here: You Didn’t Notice It, But Google Fiber Just Began the Golden Age of High Speed Internet Access