What are the most popular e-commerce platforms or where can I find a directory of these? Please categorize by type, e.g. software package such as phpshop or ecommercetemplates, or application service provider (ASP) such as yahoo stores and miva merchant. If you have (or know where to find) statistics such as number of stores using the platform, or gross revenue of those stores, that would be excellent.
I'm not writing a paper, but I am running a service for yahoo stores that feeds froogle, and I want to extend the service to other e-commerce platforms. Obviously, I want to spend development effort on the most popular platforms first. I found a top 300 retailers guide at internetretailer.com that looks promising.