Amazon to buy Goodreads for undisclosed sum

Amazon, the world's biggest online retailer that got its start in bookselling, is agreeing to buy book recommendations site Goodreads.

Financial terms of the deal were not disclosed. Amazon said Thursday that it "shares a passion for reinventing reading," with Goodreads.

In addition to recommending books to read based on what other books people have liked, Goodreads also serves as a social network for bookworms. It has 16 million members.

The deal is expected to close in the second quarter. Seattle-based Amazon.com Inc. says Goodreads headquarters will remain in San Francisco.