Back in 1995, a New Yorker cartoon made a classic joke: "On the Internet, nobody knows you're a dog." And that has long been a truism of digital culture. It's pretty easy to pretend you're someone else.

But the flip side is also true: It's sometimes hard to prove that you are who you say you are. A superb example of this paradox recently emerged at frankblack.net, the fan site for Frank Black, lead singer of the Pixies. Recently, the Pixies have announced a reunion tour for 2005, and all the fans at the site were discussing it excitedly. Then suddenly, a new poster showed up with the screen name frnck blck, claiming to be none other than Black himself.

Here's where it gets fun. The fans didn't believe it was Black. The singer is known to be awfully reclusive, so they figured it was just some lame poser playing tricks. But frnck blck insisted he was the real thing. So the fans set up a sort of celebrity Turing Test, throwing questions at him that only the true Frank Black would know. Some fans even pasted in examples of Black's prose style -- from a letter he wrote about bootlegging -- to prove the imposter wasn't real. And indeed, the prose did seem awfully different from that of frnck blck. Case closed, right?

Except that a few days later, the moderator of the web site chimed in to clarify that, in fact, frnck blck really was Frank Black. Oops.

Over at Idle Words, Maciej Ceglowski has written a superb account of this incident, and neatly summarizes the social dynamics of the Internet:

The best thing of all about this thread was watching FB try, and fail, to prove his identity on internal evidence alone. Sitting in a room together, or even on a phone line, all of the participants in the thread would have known immediately the man was telling the truth. But on the Internet, it's just text, baby.

Even more wittily, Ceglowski points out that the problem of identity-verification has been a staple of folk mythology for years:

It's the old plot of the unrecognized hero playing itself out in real life. In 1929, a Russian folklorist named Vladimir Propp wrote a book called Phenomenology of the Folk Tale, where he laid out a 31-point generic schema for all hero stories, across all cultures -- a kind of Universal Plot. The Frank Black episode is a perfect fit, if we skip all the business about him leaving home in the first place:

(23) The hero arrives home unrecognized (24) A false hero makes unfounded claims (25) The hero must perform a task (26) the hero is recognized (27) the false hero is exposed (28) the hero is given a new appearance (29) villain is pursued (30) hero marries and ascends the throne

And as it turns out, there actually was a "false hero" in this episode. After frnck blck started posting, someone else on frankblack.net pretended to be him, to try and confuse things further.

(Thanks to Andrew Rickard for this one!)