INFORMATION hygiene is a must on a website with a billion titbits about millions of books. In the case of Goodreads it is maintained by an army of volunteer editors, over 40,000 at last count, who fix misspellings in authors' names, correct page counts or ensure the right cover appears. Unlike many other crowdsourced ventures, though, the book-discussion and recommendation website is operated on a solidly for-profit basis. Goodreads, which passed 10m registered users earlier this year, taps avid readers' passion for consuming book after book—and their desire to tell others to grab, or avoid, copies. That is an abundant resource, as the (currently) 73,776th review of "Twilight"attests. It is also one much in demand. Traffic continues to grow, with the firm claiming 22m unique monthly visitors, many of whom browse without joining. A link-up with Facebook in January brought a surge of users, who can use the social network and other tools to discover and forge connections with other readers. In effect, the website is the world's biggest book club—or independent bookseller. Part of its appeal is how little the site's management inserts itself into an individual's experience, acting more like a good host at a party introducing like-minded individuals and coaxing them to chat. Once an account is created, the site's homepage turns into a list of recent activity by friends: a review written, a comment posted, a title they plan to read next. Revenue remains subdued (and secret), relying almost entirely on advertising from publishers and authors (clearly labeled as such). Unlike Amazon, whose homepage greets a visitor with things to buy, Goodreads offers idea of what to read using a recommendation engine launched last year. There is something for everyone; Goodreads' long tail is very long indeed. At present, its users have read, are reading or plan to read 360m volumes.

Under the surface, though, there is plenty of commerce ticking away, according to Otis Chandler, the site's founder and boss. Book pages link to various online stores where they can be purchased in e-book or print format. The link is subtle, but frequently used. Its focus on adding books to a "to read" list helps drive purchases, as people must at some point obtain the book. Goodreads also includes a link to the title at Worldcat, a system run by library cataloguer OCLC that lets a visitor discover if a local public lending library has a given book in its holdings.

Mr Chandler says programmes with publishers have been quite well received. After all, the site's visitors are there to find out about books, so advertisements often pique their interest. The firm's approach is to engage publishers actively. They provide advance reading copies to Goodreads members, who help to spark interest when a book is released with early reviews and buzz. (The firm demonstrates with a case study of its work with Charles Duhigg's "The Power of Habit" released early this year.)

Goodreads also encourages authors' participation. It does not act as intermediary between author and reader, though it does solicit well-known authors to participate in question-and-answer sessions that unfold over days through a discussion thread. Authors are also free to talk to and hear from readers directly whenever they wish. They may also purchase ads, whether for self-published novels or books marketed by major publishers.

Independent bookshops were predicted to be extinct by now. They remain under pressure, but continue to champion mid-list titles, which sell in the thousands or tens of thousands of copies and produce a tidy, albeit small profit for a publisher. Such stores' staff "handsell" books, making patrons aware of a sleeper they might like, some of which then sell enough copies to make the author a little money and get another contract signed.

Mr Chandler notes that a bookshop's greatness is a function of its staff's knowledge; a customer must believe that a book is being offered because it's good, and trust that judgment because of the offerers extensive bibliophile nous. In this respect, no brick-and-mortar comes close to Goodreads' collective bookishness.