From his decades in the news business, H.L. Mencken observed that “A newspaper is a device for making the ignorant more ignorant and the crazy crazier.”

Alas, or maybe fortunately, for him, he did not live to experience the Internet — which, far more than any newspaper, must be having profound if immeasurable effects on the hundreds of millions, or more likely billions, who ingest its limitless offerings. As Internet usage rapidly climbs, newspaper reading continues to decline, to the point where survival of conventional news in print is becoming doubtful.

Meanwhile, from an infinity of online sources, heads are being filled with data, information, and images, from all manner of sources — responsible, sensible, loony, exploitative, and malevolent. Fencing off children from much of this stuff has become a major parental concern, as well as a hopeless task, given children’s zest for the forbidden and preternatural facility at the keyboard.

Cervantes explains that Don Quixote became delusional because of excessive readings about chivalry. Declaring himself a knight errant, the Don rode off to rescue damsels in distress, confront giants, and fight windmills. No disrespect for the potency of the written word, but online games and pornography, especially in combination, easily exceed print for unhinging the mind. Pornography is reportedly the biggest seller on the Internet, and, if news accounts are to be believed, for Humbert Humbert emulators, it is the communications system of choice.

Has there been an uptick in bizarre and pathological behavior since the Internet became a common household implement over, say, the past 10 years? There’s no way of untangling the Internet from the many other elements of society. But one might speculate about the soaring consumption of antidepressants, a reported increase in suicides among middle-aged men, and several spectacular mass murders at universities. Violent online games, pornography, and detachment and isolation from human contact come easily to the Internet user. Is there a connection? No one can say for sure, but the possibility can’t be dismissed.

Like all technologies, the Internet is employable for good and bad, and where it is applicable to benign purposes, it can be uniquely useful. But it is easily adaptable to mischief and worse. By many accounts, it has spawned an epidemic of plagiarism among college students — and an ensuing cat-and-mouse game with professors sifting their prose online. Identity theft is another gift to online malefactors. And sheer confusion — deliberate or inadvertent — on important public matters easily flourishes on the Internet.

Under the headline “Struggling to Squelch an Internet Rumor,” The New York Times on February 27 reported a furor at the University of Kentucky concerning allegations that a course on the Holocaust had been cancelled in response to protests from Muslims. “Over the past year,” the Times stated, “faculty members and administrators … have collectively received thousands of e-mail messages … repeating the same baseless accusation — that pressure from Muslims had led the university to drop its Holocaust course.”

From whence the rumor? From an e-mailed report of a Holocaust controversy at a school in Britain — where e-mail addresses end in “.uk,” also the initials of the University of Kentucky.

No point in fretting about the Internet. It’s here to stay, bound to grow, and immune to virtually all restraints.

But don’t anyone doubt it: While it’s a blessing in many important respects, it’s also a monster.