Privacy resurged to the forefront of public debate after 9/11, and one of the more chilling examples was reports of the FBI trying to strong-arm libraries into handing over people's library records without a warrant. This was kinda dumb, since warrants are handed out like candy, and the Patriot Act forbids anyone getting such a warrant from making that fact public. It was even more dumb if you know anything about librarians; these are folks who've spent a lot of time thinking about why they're in the library business -- they don't go into it to get rich.
With that backdrop, you would think it's nuts to create a startup that relies on people being willing to give up privacy about their reading habits. But that's just what Library Thing does. Library Thing is one of the most successful book cataloging sites. You create an account for yourself, and start entering the books you have on your shelf. You don't have to expose your collection to others, but most people do. That's interesting. Why is that?
There are "social" features built in to Library Thing to encourage you to abandon the same privacy you would shriek to see your librarian surrendering on your behalf. You can see who-all owns the same book you do, or even who has "similar" collections (fat chance for me; since Paula and I are sharing an account, we are only "similar" to people who are experts in psychology, programming, and astrophysics).
But I think the basic motivation to abandon privacy is simpler. If you're going to go to the trouble to enter all your books in some digital list, you're probably a bibliophile, or at least suffering the early stages of the disease. In other words, Library Thing implicitly selects people who are invested in and proud of their book collections. Not to mention, people who have so many books that they have experienced the embarrassment of bringing home a new purchase only to find they already own it -- a disappointment Library Thing can help you avoid by letting you use your cell phone to check to see if you already own a particular book.
Library Thing lets you control your own privacy, but in some sense, simply makes it "cool" to abandon your privacy. There certainly is a Tom Sawyer component here: c'mon, tediously enter all your books, put them on display to others, and I'll let you pay me for the privilege! I'm bought in at this point because the interface is tolerable, export/import seems to work (not going to enter data I can't move elsewhere), $25 for lifetime service is cheap, and I really, really hate staring at a book at Half-Price Books and wondering if I already own it or not.
You can watch me helping Library Thing whitewash their fence by checking periodically here. By entering a shelf per week, I predict we'll have the entire collection entered before the end of 2011.