That's Not ASP!
The largest difference between ASP and ASP.NET that was discussed today is the move from VBScript to VB.NET or C#. Although much of the syntax is similar, there are a few syntax changes that can ambush a new ASP.NET programmer.
VB.NET itself introduces a lot of changes. It's now fully object-oriented, which may take some getting used to if you're a VBScript developer. Classes are used extensively throughout the .NET Framework, whereas they were seldom seen with traditional ASP. It pays to learn how to use them early on.
C# may be familiar to C++ developers, but it can be completely new for classic ASP coders. Hopefully you've seen today, though, that C# isn't really that much different than VB.NET many of the concepts are the same, it's just the syntax that is different.
Another large change from ASP to ASP.NET is the use of the event-driven model. Although the underlying mechanism for this model relies on request/response machinery, there's a new layer of abstraction that allows developers to spend more time on building applications than on digging through posted data. You'll learn much more about this on Days 5 and 6.
Appendix B, "Common ASP.NET Mistakes," lists some common mistakes that may ensnare ASP developers as they migrate to ASP.NET.