Read This: Just how many copies do you have to sell to make the bestseller list?

Anderson also discusses what he calls “invisible bestsellers”—books that are widely read but distributed through less conventional channels that aren’t tracked by places like The New York Times, Publishers Weekly, or The Wall Street Journal. He’s talking specifically about the “book bundles” released by companies like Humble Bundle and Storybundle, which curate e-book collections and sell them for pay-what-you-can pricing, generally starting at $15. Anderson’s publishing house, WordFire Press is currently working with Humble Bundle on a collection and he points out that these “bundles” wind up in far more homes than an average bestseller.

For instance, WordFire’s Sci-Fi Specials Humble Bundle sold 5,000 copies last week while books need only sell 2,571 copies to earn a spot on the Publishers Weekly hardcover fiction bestseller list. As Anderson puts it, “That means every single one of the books in the WordFire Sci-Fi Specials Humble Bundle sold nearly twice as many copies needed to hit the bestseller list. In fact, at those numbers, all 18 titles in the bundle would have qualified to land between spot No. 8 and No. 9.” But because nobody tracks these “bundle sales,” the books go uncelebrated.

Of course the big difference is that buyers aren’t specifically picking out the titles in the bundle, but Anderson makes a good point that, like most superlatives, the term “bestseller” is only useful to a certain extent.