Many people are making the leap from "access to information" to "better lives" without proper explanation of how that would work. Sure, for us it's obvious, but we're not the demographic Gates is talking about. The poorest of the poor have drastically different problems, and it's not obvious to me that they're something information can solve. "Student researching school report" seems like a good example, but much of this demographic don't even have the opportunity to go to school. And considering a full 50% of India lives below the poverty line, that's a humongous demographic.

And whatever problems can be solved by information, the poor are already making do via cheap mobile phones and their own ad hoc social networks. Which is probably the only thing that's viable for them, considering many can't even read properly and so speech is the best form of communication for them.

You could say that Internet access will create new industries and opportunities and the economic benefits will "trickle down", but 1) the timeframes are much larger (as Gates says), and 2) in my limited experience, very little seems to trickle down below the lower middle class. In fact, in India, the lower classes decry the "IT outsourcing" revolution, because prices went up across the board because the middle class suddenly had more disposable income. This did create a bunch of new jobs in the service industry, but on the whole the price increase only made things worse for the very poor.