I just had a conversation that saved my bacon BIGTIME!!
Static variables are shared across the entire server. If you declare a static variable in your web application and have ten thousand people using it, when one of them does something that sets the variable, it changes it for everyone. There does not appear to be a way to create any sort of global variable that is not also universal.
The workaround is to use the http session object instead (though this is a crime, in my opinion).
DataType ShouldBeStatic = (DataType) System.Web.HttpContext.Current.Session["ShouldBeStatic"];
What I can't believe is that this isn't emblazoned all of the universe when you google ".NET tutorial". There is nothing like it in the LAMP world. I can't imagine what sort of problems I would have suffered if I had not learned this and then the problems of going through an entire application to fix it. Bullet Dodged!