If I'd read this closer to Gibson's 
Distrust That Particular Flavor (see 
my post last month), I'd have combined them into one post, since they're very  much the same kind of thing: complete (or nearly so) collections of the  occasional nonfiction by major writers who started off solidly in the SF  camp but have since drifted in somewhat different directions, but remained solidly in favor of SF and regularly define what they do as SF. (And my  personal relationship to the two writers is also very similar: I last  read Stephenson with 
Cryptonomicon, since I fell out of the habit  with his massive historical trilogy and was out of the SF field  professionally when he came back to it.)
In 
Some Remarks
, Stephenson, non-fictionally, is  as we've always suspected: geeky in the most interesting ways, deeply  private and protective of that privacy, quirky and particular about his  working and living arrangements as only a very successful novelist can  be, and intellectually fascinated by a series of shiny new ideas in the  way of so many other SF writers. Stephenson, though, could get funding  from magazines like 
Wired to chase those shiny ideas, resulting  in pieces like the epic "Mother Earth, Mother Board," a  nearly-novel-length tracing of the state of subsea telecommunications  cables as of 1996.
Most of the pieces in 
Some Remarks bear the  hallmark of one geeky obsession or other -- Stephenson, for example, is  one of the very many SFnally-oriented men of his generation who are  still struggling with the fact that they all 
didn't get to go to  space -- though all also bear Stephenson's very particular obsessive  focus on specific minutia.
Stephenson fans will be most interested to  know that 
Some Remarks contains two of his very few short stories  -- "Spew" and "The Great Simoleon Caper" -- as well as the first sentence  of another story that will never be continued. That's not a lot of short fiction, but Stephenson isn't, temperamentally, a short fiction writer at all; he only has another story or two existent at all.
Some Remarks could  not be other than a random collection of now mostly-superseded thoughts  -- when SF writers are invited to perform journalism, there's always an  element of "tell us what THE FUTURE will be like," and that dates very  quickly -- but Stephenson's thoughts are the product of deep cogitation  and a very particular angle of attack, which makes them worth revisiting  even a decade or two later.