At first glance of this opportunity to provide a metropolitan WiFi network for San Francisco, one assumes that the provider would pay for it by either advertising or additional services (like a faster connection). But, after thinking about it longer, I believe Google wants to provide free (monitored) access to the Internet in order to improve their PageRank system.
Page Rank Explained – http://www.google.com/technology/
“PageRank relies on the uniquely democratic nature of the web by using its vast link structure as an indicator of an individual page’s value. In essence, Google interprets a link from page A to page B as a vote, by page A, for page B. But, Google looks at more than the sheer volume of votes, or links a page receives; it also analyzes the page that casts the vote. Votes cast by pages that are themselves “important” weigh more heavily and help to make other pages “important.”
Important, high-quality sites receive a higher PageRank, which Google remembers each time it conducts a search. Of course, important pages mean nothing to you if they don’t match your query. So, Google combines PageRank with sophisticated text-matching techniques to find pages that are both important and relevant to your search. Google goes far beyond the number of times a term appears on a page and examines all aspects of the page’s content (and the content of the pages linking to it) to determine if it’s a good match for your query.”
Now, imagine if Google had access to millions of peoples Internet traffic and an ability to monitor every site everyone visits. This would allow them to determine which sites are truly popular, trends on when a site might be more popular (time focus like during an event), and what sites may naturally link to other sites (following a users surfing rather then a robot?s). Let?s use a BLOG as an example. If you had a link to a specific BLOG off of CNN.com, you may think that the BLOG is quite important (let?s assume it?s a non CNN property). However, if you can ?see? that 30% of visitors to CNN.com click through to this BLOG, you can likely assume it?s an important site and thus the PageRank should be high. Let?s take it a step further since you know everything that user is doing. On the one hand, if after those 30% of people click through to this BLOG, 99% of them are off it in less then a minute, then it?s probably not that good. Thus, you?d decrease the PageRank. But, if a large percentage of people that click through linger on that site for a significant amount of time (because they?re reading all of it and enjoying it), then you can really assume that this is a hot site and that you should increase it?s PageRank.
With this level of ?visibility? into the Internet and interests of all of us, Google?s search engine would provide even more relevant and popular results for your query.
By the way, SBC and Yahoo! Provide broadband together.