"Sign-ups are beginning today in South and Southeast Austin. We’re starting with these neighborhoods, and will be opening new areas on an on-going basis."
Also, I'm pretty sure that TWC is available pretty much everywhere in Austin.
TWC is, but U-Verse isn't. Most places in Austin (specifically apartment buildings) your only option is TWC (or Grande, if you're in a Grande area).
If you look at other cities (Kansas City) only a fraction of the city (the denser, wealthy area) actually has the service 2 years later. Other large areas have been carved out entirely. Construction is "ongoing" in a number of areas but service remains unavailable. Half of the city hasn't even opened sign-ups yet - nearly 4 years after the initial announcement. A large part of KC that does have service was because Google purchased an existing fiber to the home network that already served that area.
By and large, Google Fiber is a big promise that's proving pretty tough to deliver quickly. Just google for the myriad of delays the project is facing in the cities it's "launching" in. By the time they're done launching in most of these cities by the end of the decade, the cable/telco companies will have gigabit service available in most of their markets.
"Sign-ups are beginning today in South and Southeast Austin. We’re starting with these neighborhoods, and will be opening new areas on an on-going basis."
Also, I'm pretty sure that TWC is available pretty much everywhere in Austin.