/r/aww is the 10th largest subreddit. Every one of the 19 million people there is pseudonymous, and many abuse their relative anonymity. But there are also of course the good users, our singing birds. Like /u/Shitty_watercolour, a user who paints scenes that come up in the comments and then posts them. Or /u/Poem_for_your_sprog, the user who appears without warning and replies to posts exclusively in verse.

Once, on /r/AskReddit, someone invited health inspectors to describe the worst violations they’d ever seen. A user named /u/Chamale responded with a story. “My stepdad used to be a baker,” Chamale began. The stepdad’s bakery was an authentic re-creation of an 18th-­century French fortress, and one day a health inspector came by; she was initially wary of the stonework walls and the doorless entryways, but the stepfather was able to convince her that these 18th-­century touches took nothing away from his commitment to the highest health standards. Then, as the inspector was ending her visit, she walked into a doorless building attached to the bakery. There stood an escaped cow licking all of the bread loaves.

Soon, this reply came from /u/Poem_for_your_sprog:

My name is Cow,

and wen its nite,

or wen the moon

is shiyning brite,

and all the men

haf gon to bed -

i stay up late.

i lik the bred.

Reddit has been called a lot of things: a “vast underbelly,” a “cesspool,” “proudly untamed.” And it is complicated. But it’s the good parts that I’m here to protect.

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Sometimes that means fighting zombies. Across Reddit, unused accounts pile up, the ghostly remains of a million people who have just tried out the site for a day and then given it up. What you have to look out for is when these older accounts, long since dead and forgotten, suddenly come to life—because they can be dangerous.

One night I came across a post submitted by a user named /u/Magnolia­Quezada. The title of the post was “I miss you so much,” and it consisted of a picture of two dogs, a husky and a yellow Lab, hugging over a fence. At first glance, the author seemed like a normal redditor. The account had been created 11 months earlier, a modestly respectable duration. Every account has a badge that shows its age, and older accounts are rarer and better established. Someone who’s been around is seen as one of us. Because /u/MagnoliaQuezada was many months old, it was able to bypass our subreddit’s homegrown spam filters, living and digital. But on closer inspection, it hadn’t posted a single thing. And now, having seemingly come back to life, it had shown up in my queue.

I could see that /u/MagnoliaQuezada’s user history was blank. And I could see that the hugging-dogs image was kind of blurry. That’s because it had been uploaded and shared and redownloaded so many times. Image quality goes down when photographs are compressed and recompressed by websites as they circulate online. The image had been stolen.

I checked the comments on the post. There was just one, from none other than /u/MagnoliaQuezada:

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Gibberish, perhaps the result of a malfunctioning bot or someone just typing anything to see whether their comments were automatically filtered by our moderation bots. I was now confident I was dealing with a scammer.

From dawn to dusk, scammers—be they bots, trolls, or propagandists—scour the internet searching for pictures or memes that have gone viral in the past: comfort foods, videos of things falling over, puppies. Often puppies. (Cats are also popular tools for the undead, but there are so many cats on the web that it’s tough to know which cats will attract eyeballs.) By sharing puppies, they hope that you will appreciate them, upvote them, and share them, and in so doing lend the zombie account the further appearance of credibility. It’s hard to go wrong with dogs hugging over a fence. It’s tough to accuse someone of being a foreign agent for showing you a pic of a six-week-old Labradoodle.