Bit of both.... Have you seen their new marketing ploy to get exposure for Grandcentral.com, which is a company they purchased last year. They are giving all San Francisco homeless a free voicemail for life. Everyone who has a computer, homeless or not, can get the service.
In order to get messages, a homeless person would need to find a pay phone, and pay the charge to get their messages, if there is no messages the homeless person just spent money for nothing. The other options is to have them log on to a computer and check it online. So when money is hard thing to come by for people, I don't see them spending money at a pay phone to check messages on a daily or weekly basis. I also don't see them finding a computer to check their messages either.
I like the idea behind it where people can stay in touch with possible employers and to get medical updates from a hospital, but it's just not feasible for 90% + of the homeless people so I would venture to say it was just an evil marketing ploy to get exposure for the Google service.
Just my thoughts....
Overall I love the Google search, and there push for making technology and software free for the masses.
Good article to read about Google innovation and why they do this.