In an attempt to purge trolls and spammers from YouTube’s notorious comments sections, Google introduced a radical policy last fall: Starting in November, all YouTube comments were linked to the commenter’s Google+ profile. And because they were linked to the profile, the commenter had to use his real name.

It’s an absurd notion with an Internet that thrives on avatars and anonymity and layered veils of personal obfuscation. The ability to remain anonymous online, some have argued, is what fundamentally distinguishes the Internet from “real” life. And yet, for a brief, nine-month window, Google insisted that YouTube commenters, generally considered some of the worst on the Web, put a name and face to their vitriol. At least until Tuesday afternoon, when both Google+ and YouTube abruptly rolled the policy back.

“There are no more restrictions on what name you can use,” the company explained, in an oddly apologetic Google+ post. “… we hope that today’s change is a step toward making Google+ the welcoming and inclusive place that we want it to be.”

But that line rings odd, given what we know about anonymity and inclusion in online spaces. Per a recent study out of the University of Houston, comments tend to be substantially less civil on Web sites that allow anonymity. Another academic study, this one published just this month, suggested that anonymous comments tend to be more contrarian and argumentative than identified ones.

And all that only mirrors what social scientists and philosophers have been theorizing since Plato: Whenever people know their identities are secret, they behave less ethically, less responsibly and with fewer inhibitions than they would probably choose to otherwise.

You needn’t look further than the comments section on this blog for further proof of that unsavory phenomenon — commenters, conveniently hidden behind their usernames, can get very, very ugly. Per my colleagues on The Post’s comments engagement team, moderators have recently deleted anonymous comments for, among other things, dropping racial slurs and joking about sexual assault. That kind of nonstop abuse has compelled everyone from the New York State Legislature to the Huffington Post to act.

“We are capable of doing far worse things to one another when we do not have to own up to the things we do,” the Huffington Post’s managing editor, Jimmy Soni, explained after the site banned anonymous comments last August.

And yet — despite all the documented harms! — hundreds of thousands of YouTubers revolted when Google initially announced the commenting change in November, and many similarly greeted the reversion back as welcome news. A popular petition on — which, since November, has reached 240,000 signatures — faulted Google for “invading our social life” and “trying to censor us unless we share the same worldview they do.”

In higher-brow forums, civil-rights and Internet freedom groups argued that anonymity is an important legal right, not unlike freedom of speech. Anonymity has a plus side, they insisted: as an important shield from government and commercial interests, as a vehicle for dissent and debate, as a means to take creative and intellectual risks. Essentially, they argued, online anonymity is a personal right that needs protecting.

Or, put another way, the whole debate is just another iteration of a classic and totally inconclusive social problem: should we favor the rights of the individual, or the community as a whole?

With this latest move, Google seems to have chosen option #1 (… or just given up on option #2; both seem possible.) What that means for YouTube, exactly, is unclear. Before the November change and a string of other measures to excise trolls and bullies, Youtube’s commentariat was generally regarded as one of the most spiteful and senseless on the Internet.

To this day, if you search “YouTube comments,” Google’s auto-fill will suggest the phrase “YouTube comments are the worst” — a pretty searing indictment of both platforms. And if Google, a $400-billion company with untold resources at its disposal, can’t clean up the comments section … who can?

Google has, for its part, said it will cut down on anonymous trolling and abuse in other ways; Yonatan Zunger, the senior engineer on the Google+ team, promised in several Google+ comments that YouTube had improved its moderation. This, of course, is a line some skeptics have heard before.

Wrote one, in response to Zunger: “The problem with history is that it has already happened.”