In summary Google gets closer to the consumers that they want to make money from.
1) They bring their services, and the adverts on them closer to the consumers that want it most (their servers sitting at the end of the pipes).
2) They get to trial innovative services to customers without the interference of ISPs and telcos ("Google, your new bandwidth sucking video app z that is similar to iPlayer is taking up all our bandwidth").
3) They remove the risk that ISPs could shut them off from these customers (I can see them doing buying mobile networks to get their data to customers).
4) They get information on what their customers are really doing away from search engines ("this person is searching for x, but actually downloading y").
5) They get to use their unused fibre assets.
I was always disappointed that the company Digital (DEC) wasn't more all-encompassing, maybe Google can buy the trademark and the domain digital.com and become what I wanted Digital to be?