If anyone had any doubts about how big the mobile Web will be, Google’s release of its Nexus One phone should erase them. It’s part of Google’s “careful plan to try to do what few other technology companies have done before: retain its leadership as computing shifts from one generation to the next,” the New York Times reports. And this shift is computing, shopping, gaming, info-gathering, communicating, photo-sharing, learning, teaching, producing, etc. on smart phones. Some pundits have been calling this “Web 3.0″ (and I’m not sure what else Web 3.0 would look like). According to Nielsen, about 18% of mobile phones were smartphones last year (up from 13% the year before, and a projected 40-50% of mobile phones sold this year will be smart phones. It’ll be very interesting to see how much competition Nexus One will give the iPhone, the rival it’s clearly going after. Certainly, smart phone manufacturers have the youth market in mind (see this on a hybrid of the netbook and smartphone aimed at teens).