Are you the type of shopper who walks into a brick and mortar store, looks at the products you're interested in, then leaves to order the product online? That's what Target saw happening when they began to sell Amazon's line of Kindle e-readers. Most people had never seen E-Ink technology in person and were skeptical, so would visit a local Target store and then buy the product from Amazon's website.
Target was annoyed at the fact that they were acting as a "showroom" for Amazon's products, but felt the company really crossed the line when they offered a "Price Check" application over the Christmas holiday. This app gave customers a 5% discount if they scanned a barcode in the store and purchased the product at Amazon.com instead.
Now, according to the New York Times, Target is firing back by refusing to carry the Amazon Kindle in any of their stores. They appear to be taking a hardline stance to all of their vendors going forward, stating:
What we aren’t willing to do is let online-only retailers use our brick-and-mortar stores as a showroom for their products and undercut our prices.
Since most people now know what a Kindle looks like, this move will probably have little to no effect on Amazon's business. That said, Target is flexing their muscles and showing their displeasure with Amazon by continuing to sell the Barnes and Noble Nook as well as potentially expanding the number of Apple products in their stores.
UPDATE: It appears that the spat between Target and Amazon may be growing. Amazon used to sell many of Target's products through their own website, but as of right now, a search on Amazon's site turns up no Target-based products. Thanks for the tip, Planar1280!