Hello, as I previously mentioned Commerce Server is one of the products that I support here at Microsoft and it's a product that I really enjoy supporting.
The latest version is Commerce Server 2007 and here's what the main Web Site has to say about it.
"Commerce Server 2007 enables you to create full-featured Web business applications and extend your business across networks, while allowing you to integrate e-commerce solutions within your existing infrastructure."
Here's a potted history of the Microsoft offerings in this space.
Microsoft Merchant Server 1.0 was released in 1996. http://www.microsoft.com/presspass/press/1996/oct96/intcompr.mspx
Microsoft Site Server 2.0 was released in 1997. This was the first release with a Pipeline I believe.
Microsoft Site Server 3.0 was released in 1998.
Site Server 3 was the first release I had to support. It came with various components like Search, Enterprise Content Management, a Membership Directory and the Commerce Edition which introduced me to Volcano Coffee company for the first time.
I really enjoyed supporting the Commerce elements of this product and spent a lot of time digging into how the sites worked.
Microsoft Commerce Server 2000 was released in 2000 and so once again I supported that release. This time I was involved very early on in the beta program and helped to support our Beta Customers.
Microsoft Commerce Server 2002 was released in 2002 as you can probably guess. Once again I had the chance to work on the beta support for this product. This was the first release of the product to ship with different editions.
In 2005 we released an enhancement pack for Commerce 2002 called Feature Pack 1. This introduced new management tools and new Staging Support.
Finally we have today's release which is Commerce Server 2007.
The product overview is here .
As you can it comes with systems to support a lot of the E-Commerce functionality that you might require.
Catalogs and Inventory
It also comes with Win Forms applications for the Business Management of the systems above. It also comes with Staging components and Data Warehouse Analytics Components for analysing your IIS Log files and related Commerce Business Data.
Here's a list of resources to get you more information.