I fell into Serial, the new podcast that re-investigates a murder, the way they used to say one fell into bankruptcy: slowly, then all at once. I only tuned in once six episodes had aired, but then it became a binge. A dinner with a friend interrupted me and I was palpably impatient, restless, wanting to get back to my listening. And then, when I was done, my appetite not quite sated, I satisfied my 21st-century curiosity in a prosaic way: I fired up Google.

That experience with Serial is hardly unique. Downloads of the show seem to increase each week, reportedly averaging at roughly 850,000 an episode. It’s viral. And Serial’s listeners have obsessed over it as serial readers have from the age of Dickens right down to True Detective. But in the post-listening haze, as I poked around myself and discovered the social media undergrowth amassing under it, I began to have questions about what I was participating in. Serial is, after all, not a work of fiction. It is about real people. Real people who also, as the story unfolds, have Google, Facebook and Reddit accounts. And who are really in prison, or really in danger of ending up in trouble with law enforcement, or even just with their privacy violated, as a result of all this.

But, to use a common storytelling technique employed by Serial’s host, Sarah Koenig, let’s back up a little.

If you haven’t been listening to Serial here’s all you need to know to understand this article: the podcast re-investigates a 1999 murder in Baltimore of 18-year-old Hae Min Lee. Lee was strangled on 13 January of that year, and buried in a shallow grave in a local park. Her body was only found over a month later. Lee’s ex-boyfriend, Adnan Syed, was tried and convicted of the crime. The key testimony against him came from an acquaintance of both parties, a young man the podcast names Jay. Jay testified that Syed killed Lee in a rage over the breakup of the relationship, and that he helped Syed hide Lee’s body. He seasoned that narrative with suggestions that Syed’s Muslim religion led him to kill. Syed’s friends and family, as well as Syed himself, insist he is innocent.

Sarah Koenig, the host of Serial. Photograph: Meredith Heuer/NPR

As in every crime, from those simple statements unfurl any number of investigative puzzles. Witnesses contradict each other and sometimes themselves. Jay is the latter sort of witness, a man who revised his story to the police several times. And the motive attributed to Syed, the fury a jilted ex, is both obvious and hollow. There are plenty of holes into which a person might fall, sorting these things out. In the podcast, Koenig presents herself as a person who more or less stumbled into these holes, and then got stuck there, turning around and around in the same small bit of rocky, pitted terrain.

Yet the popularity of the show, which seems to have caught Koenig and her producers (who include This American Life’s Ira Glass) off guard, has brought a lot of people to her little space, making it suddenly crowded.

One of them is Jacob White, a 34-year-old Broadway stagehand from Queens who moderates the SerialPodcast subreddit under the name Jakeprops. The subreddit has become a recommended resource for anyone listening to the podcast. It boasts 5,638 subscribers as of this writing, but its readers are probably far more numerous. A lot of journalists, I can testify, are watching it closely.

By email, White told me that he’d never been a Reddit moderator before Serial. He’s just a longtime podcast fan. He came across the subreddit very early on, and saw a post from the subreddit’s originator asking for someone to compile a list of all the “persons” involved in the crime. And when he did so, he came upon an ethical conundrum, because as it turns out these real people are exceptionally easy to track. Many of them have identifiable social media accounts.

“I feel responsible for some early breaches of privacy because of natural curiosity to fill in the holes that Sarah Koenig intentionally leaves in the podcast,” White wrote to me. “I wanted to know who and where Jay is now.” And though Jay’s last name is never given in the podcast, it is in court documents related to the case. His last name will allow you to search all sorts of databases for information including any prior offences and his address. Which redditors with a lot of database-searching time on their hands promptly did, and then posted the information they found in the forum.

Ever since their rush to cover the Boston Marathon bombing in real time led Redditors to identify the wrong suspect, members of the site have been a lot more queasy about privacy and responsibility. As White pointed out to me, Redditors have also long observed what they call an “anti-doxxing policy”, which roughly means they’re against publishing the identifying details of people who don’t want to be identified. Jay qualifies for such treatment in the view of the subreddit’s moderators, as does everyone else involved in the case. So they decided to follow Koenig’s lead; to the extent names were not given on the podcast, they would be forbidden on the subreddit, as would the posting of identifying details.

This rule has been easier to state in principle than put into practice. For one thing, the volume of posts the subreddit is hard for a few people to keep up with; White told me they rely on users to point out problem posts to them.

And there are also hard cases. The subreddit was among the first things I found when I started googling, and I immediately ended up getting drawn into a post by someone claiming to have known Syed within the Baltimore Muslim community. His post diagnosed Syed as a liar with a mental disorder.

But his personal view of Syed was less arresting than the comments below it. There friends and relatives of Syed’s came out of the woodwork to insist first that they knew who the poster was, and that that his account was hyperbolic and untrue. They all, I saw, had verified Reddit accounts. White explained to me that early on, when the moderators saw people claiming personal knowledge of the story, they set up a process by which they would verify users as being who they said they were. The range of proof goes from sending the moderators a scan of a photograph in a yearbook to a marriage certificate.

And in fact when the moderators tried to verify the identity of the person who put up this post about Syed, it didn’t work out. Whoever he was, he said he “feared retribution”. White traded a few messages with him and offered to meet up in Grand Central Terminal. “I was trying to convince him I was someone who could be trusted,” White wrote me, “but had no idea how you do that.” And a few days before the proposed meeting, the poster balked, saying he would be leaving New York to go back to Baltimore.

As a question of moderation it’s hard to say where this leaves the Reddit forum. The post is potentially libellous, but then so are some of the things Syed’s family says in debunking the credibility of the poster. That’s why, for example, I’ve been vague here in describing the precise nature of the post; I don’t want to repeat untrue statements. The moderators were conflicted; White says they took the post down at first, then restored it. He described this as “one of the most tense moments in the forum”.

The episode also brings home the fact that people who were involved in the crime may very well be reading it, too. Including, say, Jay. “My worst case scenario is that a responsible party to the murder is watching the sub,” wrote White, “gets tipped off that evidence to their guilt is surfacing, and are able to evade arrest because of us.”

Which brings us to the question of how Serial’s producers are taking all of this.

They refused to comment for this article. But White showed me a message he got early on from Julie Snyder, one of the producers of the podcast, which reads in part:

We are very cognisant of the fact that the people involved in this case are real people with families, jobs, etc, and for the people who have asked to not have their full names included in the story, we are respecting those wishes. Particularly in forums like these, where people are publicly speculating about what they think is the truth, it’s important to us that people don’t get harassed or defamed. I know you all share this concern, too. We really are still reporting out this story so we just want to caution against jumping to conclusions and certainly publicly accusing people of heinous actions. I love the discussions on the site and think it’s really incredible listeners are engaging with this story but, yeah, I have to admit I feel a pit in my stomach at the thought of anyone ‘outing’ real people or contacting them or anything like that.

White says they’ve emailed Snyder “once or twice” since receiving this message. She has weighed in on the difficult moderating cases, including the potentially libellous post. But White insists that the Serial producers “are not collaborating with us on the sub-Reddit”.

Though she does not come out and say so, Snyder seems caught a little off guard by the potential of the Reddit forum to violate the privacy of those involved in those whose story Serial is telling. In fact, when you take a look at the podcast’s website, one comes to feel they weren’t prepared for the digital aspect of their storytelling experiment altogether. They do not, for example, have a photo of Lee, the victim, up on the site at all. It is a strange omission. But then, their documents section seems slapdash and paltry; by contrast, the Redditors look like paragons of organisation.

What the Serial producers, and Koenig particularly, seem to have been relying on is the hope that people would trust them to tell the story without interference. Koenig told an interviewer on Vulture that she thinks of her process as similar to that of writing a book:

The only difference is if I was writing a book, I would do all the reporting first and then organise it like a normal person and then publish it, but here, I am releasing my work as I go, which is sort of crazy, I realize.

It is, yes, sort of crazy. It is also revolutionary. The episodic and shifting nature of Serial has (apparently inadvertently) invited a host of people to imagine themselves Koenig’s collaborators. Or, to put it another way: Reddit has become part of the story, just as much as Koenig herself already is. And this raises ethical questions of its own, mostly because the human appetite for a good story is voracious. Innocent curiosity quickly morphs into something more difficult to parse. Most journalists can tell you about a time they got caught up by the pull of a good story, only to find that the whole thing was hogwash.

Whether or not the show will explicitly address this is anyone’s guess. Sometimes it seems they might have to, as when recently it seemed the redditors had turned up a bit of information about a crucial payphone that Koenig herself had been able to uncover. And I thought it might mean something that when the publicity contact at This American Life told me that they won’t comment on the subreddit, she added: “If that changes, I’ll let you know.” But it might also just be me being caught up in the momentum of the story.