Amazon only uses colors on the top menu buttons. Amazon uses different colors for different store's sub panel. The uses are very easy to know when they switch between different stores. Border's color will remain the same for all the stores. Special Features Amazon provides a lot of different features for different store.
Borders also has the bestsellers information.
It is not as obvious as Amazon's. But it shows other sites bestsellers information. The customers can compare different sites bestsellers. It does not show how often that it is updated. Both web sites allow the customers to listen the music before buying.