BROOKE GLADSTONE: If you know YouTube, that global repository of short, mostly homemade videos, then you know lonelygirl15. But for the uninitiated, meet this summer's internet superstar, Bree, or lonelygirl, as she's affectionately known after having posted 20-something videos online.

Lonelygirl15 (tape): I'm having certain issues with my parents right now, which I can't talk about. So I thought I would bore you with a metaphor instead. My parents are unable to see things from my point of view, no matter how much I try and explain it to them. I learned how to see the world from a completely different point of view when I was four, so why is it so hard for them?

BROOKE GLADSTONE: She's in her room. She's really cute. She wants to tell you about her repressive parents, her love of science and her geeky editor friend, Daniel. She's easy to dismiss at first, but keep watching. She's kind of captivating, and she's captivated the vast YouTube universe. Fans are investigating every detail of lonelygirl, but after a summer of sleuthing, all the big questions remain, including the most fundamental – who is she? Virginia Heffernan is a TV critic for The New York Times, but lately she's been paying more attention to the small, small screen.

VIRGINIA HEFFERNAN: YouTube now shows 100 million videos a day, and it's really been the summer of YouTube for a certain part of the population that has maybe been frustrated by television or just interested in the possibilities of online video. I'm a television critic. "Rescue Me" and "Deadwood" have had great seasons, but the best television show of the season by far has been lonelygirl15. It's really involved an audience like no show I can think of – possibly "Lost" or "Star Trek."

BROOKE GLADSTONE: What kind of numbers are we talking about?

VIRGINIA HEFFERNAN: Each video has about half a million views.

BROOKE GLADSTONE: So what makes this teenager, who is essentially spilling her guts to the world, so popular? Why do you think it's up there with "Lost" or "Rescue Me?"

VIRGINIA HEFFERNAN: Part of the problem in answering almost any question about lonelygirl for someone like me, who has gone down the rabbit hole, as they say, and is now way too involved in thinking about her, is that every question requires quotation marks. You called her a teenager. Bree does say that she's 16 in the videos, but a lot of people who have watched very closely think that she's in her 20s and that she is at least deceiving us about her age, if not much, much more.

BROOKE GLADSTONE: Now, you bring up a really good point, because some people doubt who she is. And along with her enormous popularity has come a pile of conspiracy theories about whether she's real, whether she's being paid by someone. So you pose four theories for what lonelygirl could be – sweet, weird, fraud or other. So start with sweet.

VIRGINIA HEFFERNAN: The people who find lonelygirl, above all, sweet, believe that she is a 16-year-old, home-schooled girl with religious, possibly repressive parents who don't let her date, and that she has a flirtatious relationship with her video editor, who's a little bit nerdy, and that she is a very scholarly, very well-spoken, charismatic girl who deserves our attention because she's more beautiful and more interesting than any television star, and yet she's a real person.

BROOKE GLADSTONE: Mm-hmm. So now, weird.

VIRGINIA HEFFERNAN: Well, she does have these religious parents, and she intimates that she is quite sympathetic to their religion and their beliefs. She won't tell us what they are, but we have gotten one tantalizing view of what they might be in a picture on her wall, a little shrine with a candelabra that had at its center a picture of Aleister Crowley, the great English occultist who had once belonged to a Christian sect called the Plymouth Brethren and then fallen out with them and gone on to promote Western mysticism that surrounded demons and, some say, Satan worship. So you can imagine how a series that was already interesting became ‘curiouser’ and ‘curiouser’ when we all caught a glimpse of Aleister Crowley on her wall.

BROOKE GLADSTONE: [LAUGHS] So, there's weird. Now, a really vociferous group of lonelygirl watchers claims that she's a fraud.

VIRGINIA HEFFERNAN: They're not just the most vociferous. I think they're also the majority now. The videos are extremely well made, and there were clues early on that something about this didn't seem like it was just some spontaneous production by two teenagers. The group who first started saying this seems like a fraud cited the exquisite and very professional-looking video production, which you can't see on any of the other V-logs that are created by some of the other YouTube participants, and also the curious fact that the fan site for lonelygirl15, which is lonelygirl.com, that fan site was registered before she posted even her first video.

BROOKE GLADSTONE: Ah-hah!

VIRGINIA HEFFERNAN: Which makes it seem like someone was trying to create a phenomenon. And she's unfindable on Google. There's a certain wall of silence around her, which has given it the air of some kind of hoax or possibly some kind of fraud or marketing scheme.

BROOKE GLADSTONE: Did we used to be so concerned about authenticity? I mean, we have reality TV, which, of course, is famously tarted up and tricked up. So how much reality do we need before we get addicted, and how much fakery can we tolerate before we tune out?

VIRGINIA HEFFERNAN: I know that people will feel angry or betrayed if it's simply to promote some brand. I don't think anyone will be super disappointed if she's not exactly who she said she was. But we all seem to want her to be part of a kind of new art form that allows us to live in this liminal, kind of between-fact-and-fiction space that used to be reserved for reader of novels. Some people have called this "immersive play," including a theorist of these kind of games at the University of California at Berkeley, Jane McGonigal. She and others at unfiction.com are interested in games that begin to take up your whole life. What's amazing to me, and what seems like a positive result of lonelygirl, whatever, wherever she turns out to be from, is this community of essentially – they wouldn't want to call themselves this – but they're essentially doing some kind of scholarship. There are people on lonelygirl.com who've examined the botanical properties of the flora that's visible -

BROOKE GLADSTONE: [LAUGHS]

VIRGINIA HEFFERNAN: - in some of the videos that lonelygirl has put out, toward trying to figure out where she is. The message boards break down into discussions of religion, as I said, botany, technology. I ask them if they'll have their heart broken if she's not real, and they say, almost universally, they won't. Yes, they want ultimately a curtain call, I think, from lonelygirl. They want the curtain to go up and for us to see this woman and who she is and how clever she is, but not because she's some demonic trickster figure – but because she's Jane Austen, because she's George Eliot, because she's someone that has woven this amazing spell.

BROOKE GLADSTONE: Virginia, thank you so much.

VIRGINIA HEFFERNAN: Thank you, Brooke. It was great to be here.

BROOKE GLADSTONE: Virginia Heffernan is a TV critic for The New York Times and she writes about online video in her blog, called "Screens."