Whenever you do maintenance work on a website it is advisable to show the visitors a nice message telling them politely to come back later, rather than a nasty error, or even worse: a big Yellow Screen of Death.
Since ASP.NET 2.0 came out of the labs of Microsoft, there is a way to take a web application down using the “app_offline.htm” approach. You simply create a HTM file, which you then upload to the server, and if there is any request to this web application, IIS will automatically show the contents of the app_offline.htm file. Once uploaded, most people only rename the file so that it doesn't catch up with IIS anymore, and the site is already back online. » Continue reading ...