This article is by Technical Evangelist Michael Jurek. He has written a couple of IIS 7 modules that I use extensivly in demonstrations. Technically, this is a handler rather than module, but the point is the same - to illustrate how you can use managed code to modigy the behavior of the http request processing pipeline.
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dniis/html/iis7run.asp
This article includes code for a managed handler as well as how to add a page to the IIS 7 UI to configure the applicaation. Extending the IIS 7 schema is also involved.
The handler itself adds a copyright and optiona watermark to any .jpg. After this handler is installed as global module, then any .jpg on the server will have a watermark and copyright on it when renederd by the server. Very cool. All you ahve to do is drop the image on the web server, and IIS 7 takes care of the rest. My guess is that there are great many sites that deal with images for sale that are going to be intrested in something like this.
Just take this idea and stretch it out a bit. What if you wanted to process other kinds of content in some other way. For example, say you wanted to have every page renedered by the server or some folder delivered as a pdf. Perhaps add a special tag to a URL like /?ShowasPDF and have a module pick up the tage and convert the output on the way out?
How about a moudle that took an Office document and striped out comment and revision for unathenticated users? Attached corporate metadata, encryption, tags, disoclaimers to all office documents delivered by the server?
How about a module that dose CardSpace authenticaiton, langugae translation, convert to speech, or send any page to an email address?
The possibilites are endliess. This is going to be fun stuff.
-brett