And fighting obscenity can be good for business. Impermium, a Silicon Valley company that helps Web sites deal with unwanted reader comments, has begun marketing technology that identifies “all kinds of harmful content — such as violence, racism, flagrant profanity, and hate speech — and allows site owners to act on it in real-time, before it reaches readers.” Impermium will police the readers — but who will police Impermium?

Apple, too, has strayed from its iconoclastic roots. When Naomi Wolf’s latest book, “Vagina: A New Biography,” went on sale in its iBooks store, Apple turned “Vagina” into “V****a.” After numerous complaints, Apple restored the title, but who knows how many other books are still affected?

True, these books are still on sale. Unlike the good old United States Post Office, which once confiscated “Lady Chatterley’s Lover” and other books it deemed too lewd, Silicon Valley does not engage in direct censorship. What it does, though, is present ideas and terms that have gained public acceptance as something to be ashamed of. Silicon Valley doesn’t just reflect social norms — it actively shapes them in ways that are, for the most part, imperceptible.

The proliferation of the Autocomplete function on popular Web sites is a case in point. Nominally, all it does is complete your search query — on YouTube, on Google, on Amazon — before you’ve finished typing, using an algorithm to predict what you’re most likely typing. A nifty feature — but it, too, reinforces primness.

How so? Consider George Carlin’s classic comedy routine “Seven Words You Can Never Say on Television.” See how many of those words would autocomplete on your favorite Web site. In my case, YouTube would autocomplete none. Amazon almost none (it also hates “penis” and “vagina”). Of Carlin’s seven words, Google would autocomplete only “piss.”