Pablo Defendini pointed me at this:
I’ve been thinking a lot about internet snarkiness lately, and what I keep coming back to is that snark was a defense mechanism that evolved perfectly in the truth-deficient, cynicism-rich compost heap of the Bush era. [emphasis Steve's] When most of everything that’s told to you is bullshit, it’s easier to treat everything with suspicion. Genuineness is met with skepticism. Enthusiasm with ridicule. Optimism with derision. It’s easier to keep things at arm’s distance that way – keep them where they can’t hurt you.
A Post-Snark Era? From Enter the Octopus