PortalPageFilter makes your dynamic ASP Web site look to the outside as if it were static - thus enabling spiders (Google, etc) to index your entire site. On the inside, however, you don't have to change your ASP code.   Code: ASP.NET v2.0

The ASP.NET Version Switcher is a little utility that can be used to quickly switch the Framework version that the ASPX pages are compiled against. This is helpful for developers who have to test their apps for compatibility with different version of .NET   Code: ASP.NET v1.0 & C#