I suspect you're trying to solve the wrong problem: figure out how to deliver content at connection speeds these underserved areas can sustain. Not DSL, 4G, 3G...but GPRS/CDPD bandwidths (circa 56K-384Kbps). Dictionaries & textbooks can be delivered as text (or slightly more overhead, Unicode/UTF-x for multilingual), encyclopedias/wikis slimmed down, images downsized, many instructional videos can be delivered as something much less than 420p, etc, etc. More...you shouldn't need 2MB of JS to read the internet equivalent of the newspaper. Proxies/Gateways can translate. Make it efficient for people to access information at speeds that are accessible and affordable to their circumstance without the glitz/useless eyecandy and you could change the world.
Oh...you'll have to deal with all the folks claiming life-as-we-know-it-will-end if they can't deliver a dozen or two multiMB ads and gobs of clickbait to those 2.5B people, whether the users can afford to receive them or not. That's probably what'll kill the idea.