Amazon Remembers allows you to take a picture of an item with the iPhone camera that you want to remember. The photo is stored in the app and uploaded to the Amazon Web site where a human reviews it and attempts to find a match for the product in your photo. When they find a match Amazon emails and alert with the requisite links to the product.
It works quite well. While on vacation in Florida I quickly realized that I was going to need an additional battery for my new Panasonic Lumix LX3 digital camera (Disney has a way of wiping out a camera battery). I whipped out my iPhone, tapped Amazon Mobile, then the "Remembers" icon at the bottom. I popped out the Lumix battery and snapped a quick picture with the iPhone.
Before I got home that day, I had an email from Amazon that read:
Dear Amazon.com Customer,
The Amazon Remembers service has found a product similar to the photo you recently submitted.
You may view the result from your iPhone here: Amazon Remembers B000F1TD2A (that's an iPhone link)
If you prefer, you may view the result from your web browser. The result has also been posted to your Amazon.com home page and Your Lists (link available at the top right of any page on the Amazon.com site).
Thank you for using Amazon Remembers.
P.S. If you would like to stop receiving these e-mails, you may turn off Amazon Remembers e-mail notification from Your Account in the More section of the Amazon Mobile app.
When viewing Amazon site, I'm also reminded of things that I've asked Amazon to remember. They're prominently displayed at the top of the page (like the picture at right).
Needless to say I purchased the battery (a Panasonic CGA-S007A/1B Rechargeable Lithium Ion Battery, $30) almost immediately and it's probably already waiting for me back at home (courtesy of Prime) – just in time for Macworld Expo in San Francisco.