I run a small Yahoo! Store which you can view here. While I like coding in Perl, there are some SERIOUS advantages to being a Yahoo! merchant which compensate for most of Yahoo!'s shortcomings.
in reply to interchange for e-commerce?
Advantages of Y!
Being indexed into Yahoo! Shopping's search (HUGE)
Merchant account, cc processing, security, availability
Quick and Easy to get online fast
Disadvantages of Y!
Inventory control does not work
Lack of Returns Processing
Lots of merchants don't like their ratings system
Customers can't find out shipping cost until they are just about to place orders.
All in all, Y! Shopping is a very good deal IMHO.
I like chicken.