The prevalence of things like Shakespeare and classical music is mostly a writing conceit--it always comes off as contrived and awkward when Star Trek writers either invent futuristic forms of art or awkwardly shoehorn in the 20th century.
I would posit that the world of Star Trek eliminates the alienation of everyday life on Earth that leads one to social networking in the first place. Furthermore, and this is admittedly handwavy, but any analog to the internet would either only cover the station itself (in which case why bother, because the whole station hangs out at the bar anyway) or require subspace radio to communicate with thousands of planets at once, which is very plausibly impractical if not outright prevented by security requirements.
More nitpicks:
> 90s! YOU WERE THE BEST! With your adorable WE ARE SO DARK plots that seem like Strawberry Shortcake Goes to Space by today's standards.
Well, compared to BSG I guess there's no on-camera rape scenes, but all the rest, torture and genocide included, is there. It isn't portrayed with the same realism, granted.
> In fact, the war correspondence he so longs to write--and he believes he is the only one who can write it--would be one of many, many voices escaping from occupied DS9 in the post Arab Spring networked news hivemind.
Well they evacuated nearly all the civilians. Jake is quite possibly the only civilian left who doesn't have anything better to do than to be a war correspondent. Quark has his bar, Rom has his undercover mission, and the Bajoran crew are still military officers who have to run the station and pretend to collaborate with the Dominion.
To the point that "nobody blogs", the actual crew all keep "personal logs", and while they're classified and not shared to the world (more on that later), it's not that far off.
> Can you imagine the subreddit for the station? How many atheists would tear down Sisko the messiah, how every decision would be questioned, mocked, dissected where the actors and the acted upon could see it?
Who, exactly? The crew? No, that would be insubordination. The crew's families? Not technically insubordination but still awkward. The business owners on the Promenade? Right, Quark and the owner of the Klingon restaurant are going to openly criticize the one thing that makes DS9 a tourist destination for Bajoran pilgrims.
> Because of this, and because of the lack of a social network, it is possible to be alone in the Star Trek world in a way which I would have to deliberately take action to achieve in my world. Even when we are alone, most of us check a number of communication vectors and leave them live--Twitter, email, text messages, Facebook, our blogs, Reddit, news feeds. We are a baby hivemind spinning our training wheels. To be alone as profoundly (to me) as Sisko, Kira, and the rest often are, I would have to make a decision to shut down all of those streams.
These people are living in space. Only the highest ranking officers have their own quarters, and the unmarried ones seem to spend half their leisure time dating or hanging out in the bar. Even the station commander's son has to have a roommate when he moves out of his dad's quarters. There's even a scene where Worf and Odo, the introverted loners of the cast, discuss their respective strategies for getting away from it all to finally spend some time alone.
EDIT: Come to think of it, the station does have a network. Quark is constantly hacking into it, probably with Rom's help. In one amusing scene, he does it to spam everybody with poorly produced advertisements for his bar: http://www.youtube.com/watch?v=w-9tw2mx_gE