How the Pieces Fit
The preceding analogy isn’t as silly as it looks. To break it down a bit, consider the pieces that make up the new Excel features:
Note
Things that make life easier for some often make things more complicated for someone else (in this case, us). Understanding XML and its related standards is a major undertaking. Fortunately, Office often lets you take a high-level view.
Workspaces and lists are documents and document fragments that you create in Excel and share through SharePoint services.
Lists exist as XML data which is imported or exported through Excel.
These pieces all interoperate by means of web services.
Finally, InfoPath is the form engine that collects data and stores it as XML.
Figure 1-2 illustrates how these pieces fit together. The XML flowing between each piece is called a data stream . Figure 1-1 is not really off the mark.

Figure 1-2. XML-based features cooperate behind the scenes
Underlying this interaction are two pieces that I don’t know how to fit into Figure 1-2 legibly:
Note
If you explore a SharePoint server, you won’t find any list, workspace, or even XML “files” - it’s all stored in SQL! In fact, that’s the way the next generation of Windows works; Longhorn is backed by SQL.
You can program Excel and these other components using Visual Basic .NET. You can still use VBA in Excel, but VB.NET provides a better programming platform ...