thanks for explaining this.

A hosting billing solution (at least my interpretation of your question) is an application a hosting provider would use to bill their clients. 1 time or recurring (monthly, quarterly, yearly) - Ideally, it should be integrated with their plan management application..

A shopping cart is a script used to house and display your products/services and allow customers to purchase them by "adding" then to a shopping cart (hence the name), then checking out..

Hope this helps...

I think the way the market is evolving, that surviving software are actually doing both, hence why the line gets muddled a little bit. I know that we have been doing both for this reason for awhile now.

Best regards.
Alexandre