Free Wi-Fi for Mountain View

Google is about to (due Sep 23) give its hometown a municipal wireless network covering all of Mountain View, with free Internet access for both residents and visitors. You'll need a Google account to log on.... More here

My best guess is that they are using the local population to trial what they intend for all the USA. I doubt that requiring people to log in to a Google account is worth Google's while, unless they figure that:

a) Once a huge range of Google services are available, all ad-supported, providing a free Wi-Fi service is worth it to gain customers

or...

b) There will be ads appearing that relate to every page the user visits, in a window that you can't get rid of