Amazon.com's North American stores are not functioning at this hour and there is no word when the stores will return to full operation.

The sites allow product searches, but detailed information for music (albums don't list songs) and book titles are incomplete. And the ability to place an album or book in a cart -- whether it's Cyndi Lauper's "Memphis Blues" or John Sandford's "Storm Prey" -- yields the similar message, "The item that you tried to add to your cart is not recognized by our catalog. To find the item that you're looking for, try using the search box at the top of the page."

Sources say the site has been down since 12:30 p.m. PST. Beyond the U.S. and Canada, Amazon stores elsewhere in the world appear to be functioning.

Amazon did not immediately respond to inquiries at press time.