One thing I've found is that reading about people's lives on the internet has widened my conception of what kind of lives are possible. Other than reading the biographies of exceptional people, people's life paths used to be totally dictated by TV and local society, where people's lives were generally restricted to: working for someone else, having traditional heterosexual relationships, getting married, having kids, getting old and dying. If this was unsatisfying to you, the only real option that was advertised was: work for someone else, have a traditional heterosexual relationship, get married, have kids, and spend your free time imagining how much more awesome life would be if you were working for someone else, having a traditional heterosexual relationship, and getting married except as a member of Starfleet in the 24th century. (In recent years, or on premium cable channels, those possibilities were opened somewhat.)

The "open" internet has taught me all about startups, open relationships, polyamory, child-free living, "dropping out", entheogenic spirituality, transhumanism, anarchism, libertarianism, socialism as anything except a caricature drawn by its enemies, progressive metal, Lisp, and tons of other things. None of these are new ideas, and they're not all great ideas either, but where else would a shy, sheltered kid from a hick town learn about them? It's the long tail applied to everyday human experience, and the full consequences of that are going to be indescribably big.