I have read several ASP.NET 3.5 and 4.0 books that begin explaining a concept with something like "in classic ASP it would have been done like this."
Why do ASP.NET 4.0 books still refer to classic ASP? Are there really that many developers jumping from Classic ASP directly to ASP.NET 4.0 or is it just force of habit?
Programming web applications in classic ASP meant programming at much lower level, ie one needed to know more about the stateless nature of the web and the techniques to pass infromation between the server and the client. Having done a lot of asp work before moving to asp.net webforms made things easier to resolve when there were problems, now that MVC is around, knowing asp has become even more useful as it is less abstracted.
I suspect a lot of web developers using ASP.NET have come from a classic ASP background and its easier to compare/relate with as its also a Microsoft technology.
I would guess that the "latest" ASP.NET books are mostly just lightly-updated versions of books that first came out when ASP.NET was new. You're right, though, that's a pretty dated reference by now. It's like making fun of the Rolling Stones for being so old, when you should be making fun of the Smashing Pumpkins for being so old.