Aha!  Robert Scoble has stepped boldly into the breach, and explains .NET! 

According to Robert .NET is three different things:

1. .NET is a programming platform.  As Robert describes it, .NET is a different way to create OCXs, that is, the newest incarnation of COM.  (It took me a long time to get COM, too.)  There are two parts, a framework (APIs?) and a runtime (the infamous 20MB .NET CLR).  Okay, I get this.
    
2. .NET is a set of protocols.  Basically SOAP.  Okay, I know SOAP, it is like XML-RPC.  I find XML-RPC to be cleaner than SOAP <sorry;>, but I get this.
    
3. .NET is marketing.  This is the part which probably threw me, and others also.  I'm fine with marketing, but labelling stuff with a "brand" which doesn't have an anchor is silly.  Not to mention it dilutes the brand, and it confuses people :)

This actually helps, thanks, Robert.  Microsoft should copy your post to the top of their What is .NET page.  And the GotDotNet guys should, too.  I still think .NET is a crummy name, OLE was better ;)

I'm going to mull this over; I'm not ready to say "I get .NET" - yet.