Amazon said on Tuesday that it bought Web site Shelfari, owned by Seattle startup Tastemakers, for an undisclosed amount, according to BusinessWeek. Shelfari lets book lovers post profiles, organize book groups online, and create "virtual shelves" of their favorite titles, which they can then recommend to other readers. The idea behind the purchase is pretty clear: with Shelfari, Amazon could populate its Kindle e-book store with community-based tools.

"Kindle has hit a nerve, and it represents the future of electronic books," said Tim Bajarin, president of industry consultant Creative Strategies, in the article. "Over time, these social networks [will] add great value to the experience." At the same time, the deal has raised a few eyebrows over at Shelfari competitor LibraryThing, where founder Tim Spalding had plenty of harsh things to say about whether or not Amazon is crossing a line.