The Long Tail is Chris Anderson's blog, former Wired editor, about long tail economics, free business models, and web startups.
HN links it for Anderson's responses to critiques of the long tail idea, including the HBR piece, and for his survey of free business models.
It's less common but hardly unprecedented.
1. Charles Stross (one of the four examples above) used to point readers to BitTorrent for his free book downloads: http://web.archive.org/web/20090514034859/http://www.antipope.org/charlie/accelerando/ (And he complains about automated scanners flagging legit files as copyright violations: http://www.antipope.org/charlie/blog-static/2009/11/imbeciles.html )
2. Unni Drougge use The Pirate bay to post a torrent of an audio version of her best-selling novel: http://www.p2p-blog.com/item-1029.html
3. Larry Lessig releases his book "Free Culture" as a torrent: http://lessig.org/blog/2004/03/free_culture_is.html (And of course, a USC student had his network account disabled for downloading this completely legal torrent: http://boingboing.net/2006/08/25/universities-put-hol.html )
4. Dan Morrill posts a torrent link to his book about selling e-books: http://torrentfreak.com/my-book-please-081017/
5. Megan Lisa Jones self-publishes a novel through BitTorrent: http://ibla.us/2011/content/thoughts-on-the-bittorrent-promotion-and-monetizing-a-book/
6. Caris O'Malley posts a pirate torrent link of his own novel and encourages readers to download it: http://hipsterlibrarian.com/2011/08/04/illegally-download-the-egg-said-nothing-today/
7. Wired editor Chris Anderson links to a torrent search for his book "The Long Tail": http://www.longtail.com/the_long_tail/2007/02/books_want_to_b.html
He admitted so on his own blog.
I remember him saying that the new data didn't really change anything and explaining why the long tail idea was still valid.
edit: This is what I was thinking of: http://www.longtail.com/the_long_tail/2008/06/excellent-hbr-p.html
So in the data she cites, the head of the online music market represents 32% of the all plays, and the tail represents 68%. That's certainly no challenge to the Long Tail theory; indeed, it's even more tail-heavy than the data I cited in my book (probably because I used a more generous estimate of 50,000 tracks for Wal-Mart's inventory).
I didn't like the subtitle though: Why Chris Anderson's theory of the digital world might be all wrong.
Anderson explains on this blog (http://www.longtail.com/the_long_tail/2008/06/excellent-hbr-p.html ) that Elberse uses different definitions for 'tail' and 'head'. So it's all about definitions, rather than having posited wrong claims.
The article's author never disproves Anderson's theory. So it's a bold statement to say it might be all wrong.
'... Some say that the bubble is fully inflated once journalists start launching startups. ...'
I wish journo's would do some basic fact checking (still requires verification though). Clearly from his about page '... background is in science, starting with studying physics and doing research at Los Alamos and culminating in six years at the two leading scientific journals, Nature & Science...' ~http://www.longtail.com/about.html
According to Wired's Chris Anderson it's all but dead. His coming book is about this very subject, called "FREE". Until the release, take a look at this article (and video clip) by Anderson himself: http://www.wired.com/techbiz/it/magazine/16-03/ff_free, or at his own blog (which lately have been featuring several articles about "free"): http://www.longtail.com/the_long_tail/2007/05/my_next_book_fr.html
To cheer things a bit, here are some higher numbers:
Flickr: 5-10%
Ning: 3%
Online free-to-play games: up to 25%
TurboTax Online: 70% (!!)
Source: http://www.longtail.com/the_long_tail/2008/11/freemium-math-w.html
My opinion: it depends on a lot of factors. From my experience without much effort you can get 1% users convert. But like I said there a lot of variables that can mess it up or down.