Arianna Huffington and Oprah Winfrey have a lot in common: They're both on TV a lot, they both love Barack Obama, they're both full of advice for how you should live your life, they both endorse dubious medical theories, and so on. And, as of this week, they both have book clubs. But does Huffington have Winfrey's magic touch?

Much has been written about "the Oprah Effect": Winfrey's uncanny ability to turn just about any book (or other product) she recommends into an instant best-seller. I tracked the Amazon.com sales rankings of In Praise of Slowness by Carl Honore, the inaugural selection of "Arianna's Reading," Huffpo's new book club, to see if there's an Arianna Effect.
On Tuesday morning, hours after the selection was announced, the hardcover edition of In Praise of Slowness stood at No. 100,809 among all books. The paperback edition was at No. 33,736. Two hours later, both editions' rankings had skyrocketed: the hardcover to No. 6,423, the paperback to No. 2,400. By late afternoon, a few minutes before the end of the business day, the hardcover had risen to No. 825, while the paperback had climbed all the way to No. 151.

But then they peaked and, at some point overnight, began to fall. As of 10:24 Wednesday morning, the sales rankings stood at 1,988 for the hardcover and 182 for the paperback. And they've been falling rapidly since then.

In other words, Huffington's blessing is enough to produce a marked short-term spike in book sales, but she has nothing like Winfrey's staying power.