"Unless you have a written agreement with Google Fiber permitting you do so, you should not host any type of server using your Google Fiber connection, use your Google Fiber account to provide a large number of people with Internet access, or use your Google Fiber account to provide commercial services to third parties (including, but not limited to, selling Internet access to third parties)."

That is an "or" so no servers at all without written permission. This text is referenced from the TOS as examples of what you shouldn't do but the wording isn't actually in the TOS.

Reasonable use shouldn't make a distinction between incoming and outgoing. If I'm making 10 req/sec to a server in the cloud, how is that any different than someone making 10 req/sec to a server in my living room?

I remember when the internet was seen as a many-to-many communications medium. Have we given up on that premise?

Unfortunately, that pretty much went out the window when residential ISPs realized they could get away with 25mb/s down and 0.5mb/s up. Which was a while ago.

What if I am hosting a Quake match with 10 simultaneous requests, is that outside of reasonable use?

I was thinking the same thing, or even running a Minecraft server. They need to publish examples. Gaming servers like this would probably be considered OK. They're most likely targeting examples such as someone starting up their own mail server, even if just for personal use.

Running your own personal mail and file servers should be the default in a truly symmetric many-to-many internet.

I would say the line would be crossed if people made money with their hosted content.

The problem is they don't spell out what reasonable use is, or mention "enterprise-level". They simply have a blanket ban on an entire class of applications; anything that listens for and accepts connections is a server.

I don't think that's the point, though. ISPs wanted to charge businesses extra fees for high bandwidth use and they were backhanded to the face. Now Google would like control of high bandwidth use (well, their response vaguely says "any kind of server") in a similar fashion. I think semi-arbitrary rules to distinguish business from consumer usage is a red herring. It ultimately comes down to, can a business charge extra for varying levels of bandwidth usage or not? Google said no when it wasn't an ISP, and now it's saying yes.

Selective enforcement is the most abusable. The goal should be to preempt abuse.

Maybe they are OK if you host a blog, but then maybe if you host a blog critical of them they make you drop of the net.