Unfortunately, you can't host a server on Google Fiber. It falls under misuse and is a violation of their ToS. I am not aware that it was originally forbidden, but it is now unless you receive a written agreement. Whether or not it will be enforced is another question.
I am not saying I wouldn't subscribe to Google Fiber either. But I think a lot of people won't because of price.
That's just one of the standard silly clauses every ISP throws into the ToS. That's their way of telling you that you have residential service which is not supposed to be used for business purposes (profit or non-profit). However, there's nothing specifically non-residential about having a server. It's all about the kind of traffic you get. I've had no need to run a server for some years now, but if I did have a need, then I would--regardless of the ToS. I would, however, never try to run a business using residential service; it would only be for personal use. -- "...but ya doesn't hasta call me Johnson!"