said by delusion ftl :
If you had 1gb data link to your customers could you theoretically move all tv content (including HD and on demand). Read: Can you supply simultaneous 1080p (and higher with 4k coming) streams to 2-3 devices per subscribed households. And can you do this on a typical sized coax node?
Not only that, but if you were able to move your channels to the ip link you could theoretically (there may be some regulatory hurdles) sell Comcast TV (and phone) to the Google fiber subscribers running your set top boxes with your payperview and your advertising, potentially undercutting and outperforming any TV service they may be trying to sell. And all this in a market that you put no capital in, nor have hard cost structures to maintain. Seeing as how you have decades of more experience with this than they do, I think it would be something worth exploring while you still may have an edge.
Google, like Uverse, uses IP multicast for live TV channels. This basically means that there is only one copy of the channel on teh backbone and it gets propagated to the edge if someone is watching/recording.
Video on demand and network DVR is unicast like youtube - each viewer gets sent their own copy.
It is much cheaper and easier to do the multicast version than the unicast- it scales a lot better.
However, network routers need to keep multicast address tables that hold the info for each multicast channel. This table size is typically pretty small - 2-4k, which sounds like a lot until you have HD/SD/small versions of each. I think this is one reason that Google isn't allowing other people to deliver normal live TV service over their network. You also have the problem of allocating these addresses. I assume that Google is blocking outgoing multicast from homes, since you could basically do a DOS on TV service very simply.
Google TV is interesting as it is the first service designed for high bandwidth networks, Uverse has solved a lot of the same issues, but having a bigger pipe simplifies the problems somewhat.
Advertising for live/cable TV is weird anyway - as the cable/Uverse/Google service provider you can't monkey with the content except is contractually defined ways. For example, you don't get to insert any ads into the local off-air channels - CBS,NBC, ABC, etc. - and only a couple of minutes per hour on most cable channels.
If you use unicast to deliver live TV service, then you end up with a monster server farm to deliver content to whatever the peak viewing is for your area - i need one stream for every viewing device. This ends up being really expensive, at least for normal companies (google could leverage their YouTube infrastructure, which I assume they are for VOD).
Will be interesting how much Google opens this up in the future. Is still a closed network for live TV delivery.