When he’s not jacking off to steampunk bullshit, Cory Doctorow can write some pretty compelling sentences. This particular essay neatly lays out the reasons I value Science Fiction. (Please no wedgies.)
Mary Shelley wasn’t worried about reanimated corpses stalking Europe, but by casting a technological innovation in the starring role of Frankenstein, she was able to tap into present-day fears about technology overpowering its masters and the hubris of the inventor. Orwell didn’t worry about a future dominated by the view-screens from 1984, he worried about a present in which technology was changing the balance of power, creating opportunities for the state to enforce its power over individuals at ever-more-granular levels.
[Since that site has a layout best described as buttshit, I recommend you use Readability.]