good info above, just some more background here, fiber internet refers to optical fiber, or wires made of many small (about human hair sized) strands of silicon dioxide (basically glass) which are used to transmit messages by light rather than electricity like in metal wires. Turns out fiber can transmit more information further and faster than electricity without as many repeaters (basically signal boosters which require power and stations set up along the route of the wires which carry the internet to everywhere) so the core of the internet, the backbone if you will, is mostly made up of fiber because less cost for repeaters and higher bandwidth. Your general cable ISP runs fiber to a center near your neighborhood and then splits that up between everyone there by running cable to the homes. Some fiber to the home has been offered by the conventional ISPs but the reason google fiber is such a big deal is because they are offering speeds about 50-100x faster than competitors for about the same price. With the established ISPs like Comcast starting to employ data caps (250-300GB/month not due to network congestion, just kind of a screw you customer) and the market basically being a monopoly, google fiber came in and offered all the speed and no limits to try and disrupt the market and stir up competition. Which is happening slowly because it takes a long time to build out a fiber to the home network, but it is happening, in areas with google fiber available the entrenched ISPs charge less to be more competitive.

and just some networking background for OP, networks operate on a layered system, and for the internet layer 1 is the physical medium like the copper wire or fiber line or radio signals through wifi. Layer 1 handles the actual phsyical transmission of the data. above that, layer 2 is usually the MAC or ethernet layer (also sometimes layer 1 and could be other protocols) and is used to transfer the data in packets and sometimes for error correction. layer 3 is the network layer and is most commonly the IP layer, where your IP address comes from. layer 4 is most often TCP and above that is the application layer which is your basic HTTP/FTP/SMPT(email) protocols. That is confusing and simplifying most of it, but some more info can be found here

Basically the highest layer contains the actual info being transferred and is split into packets with a header and some tailing data to let the other end tell when the packets start and end. The lower layers also put a header on the packets which will tell the computer and the routers and such in between how to get the data from your computer to the destination. There are many different protocols to send data around (standards to define how all the data, the actual 1's and 0's will be interpreted by the other end), and different higher level ones can be used with the same lower level ones.

Anyway, this got super long and I could keep going on (computer engineer with a few hours to spare) I feel like this is enough info. Also, I wish I had google fiber.