On some days, cracks appear in the Internet. Thursday was one of them. A chasm appeared between Reddit and Gawker, and several casual users tumbled into it and were destroyed in flames. Tumblr got involved as well.

It started with the Reddit forum CreepShots, where users of the popular Web forum could post stealthily taken photos of women.

Then someone decided to fight back with a Tumblr called “Predditors,” outing the CreepShots posters’ real identities. Latching on to the CreepShots forum’s own rationale that it was “technically legal,” she told Jezebel writer Katie J.M. Baker that she was “doing something that is technically legal, but will result in consequences for their actions.”

The anonymous tipsters behind Predditors even managed to obtain a real-life arrest.

But Tumblr soon took Predditors down (it’s back up), and when word spread that Gawker was about to out one of the forum’s moderators, large swaths of Reddit began urging boycotts of Gawker and its media properties, including Jezebel.

The day’s skirmishes raise a number of questions, some easier to answer than others.

Someone cynics might look at this like Europe before World War I and pronounce the entrenchments inevitable, natural outgrowths of the differing personalities of the nations that make up each site. After all, Jezebel, loosely defined, is an assortment of People Least Likely to Think That Posting Creepy Photos of Ladies Online Without Their Consent Is Okay.

But that’s too simple. You can have dual citizenship. The person behind Predditors said she was a Redditor herself.

Whenever online life spills over into real life, it’s messy. Loss of anonymity can be a fate worse than death. The tales of bloggers forced into hiding by harassment online and off are harrowing and ubiquitous. Lose your anonymity, and sometimes you wind up off the Internet for good.

Reddit specifies in its FAQs that “Reddit is a pretty open and free speech place, but it is not ok to post someone’s personal information, or post links to personal information. This includes links to public Facebook pages and screen shots of Facebook pages with the names still legible. We all get outraged by the ignorant things people say and do online, but witch hunts and vigilantism hurt innocent people and certain individual information, including personal info found online is often false. Posting personal information will get you banned.”

I sympathize, up to a point. I believe in anonymity. Sometimes, open expression on the Internet is closer to free thought than to free speech. Free speech comes with the implied limitation that you have to be willing in most cases to stand by your words and not hurt people. But you can say things behind a mask that you wouldn’t with your own face. For better or for worse. And in many cases, the mask is exactly as flimsy as those masks in films. The Lone Ranger and Batman are only mysterious and elusive to identify by our mutual consent. It’s the Emperor’s New Clothes conspiracy. We act as though everyone is wearing a mask, when really — as Predditors showed, quickly — most of us leave constant trails identifying ourselves. We are always one marginally skillful hack away from being found out. For dwellers in the masked corners of the Internet, where everyone agrees to anonymity, this is an alarming thought. It undermines the foundations.

But there’s always a ‘but.’

And in this case it’s a question of choice.

Since the imbroglio started, CreepShots has been banned and shuttered, as has its replacement Creepyshots. Creepsquad is, at time of writing, carrying the banner, mournfully, warning users to be safe and take precautions to preserve their anonymity.

If only the women in the pictures were so lucky.

It’s a violation when you don’t agree to be revealed. But this goes both ways. When you take choice away from the people you show, don’t be alarmed when they try to take yours.

Fight fire with fire, blog with blog, technically not illegal activity with technically not illegal activity.

T here’s a fairly easy distinction here: You don’t want to be at risk of being outed for posting creepy shots? Then don’t post the shots.

You can choose not to take a creepy picture, but the person in the picture can’t choose whether to appear in it. If people could magically vanish from images they didn’t want to be in, Anthony Weiner would still have a vibrant political career.