Definition of Extensibility- The ability to add new features to an existing program without disturbing any existing code.
www.it.bton.ac.uk/staff/je/adacraft/glossary.htm

For quite some time I have been speaking about IIS7's extensibility and the great potential this feature holds as it allows to shape IIS7 into whatever your needs are by writing modules that tie right in the iis7 pipeline.

The best way  to explain this concept is by showing a demo of the DIRECTORY LISTING MODULE written by Bill Staples.

Here is the way IIS7 ( and it's predecessors) display folder content via http when the

Directory Listing option is turned on:

Here is the way IIS7 ( and only IIS7) displays the same content.  However, in this case the DIRECTORY LISTING MODULE has been turned on. Learn more about this module here.

Link-  http://ccaneja.poweredbyiis7-appliedi.net/ninja/ This will allow you to view the functionality of this module.

The real beauty here is the no need to deploy some 3rd party ASP.net application in order to create this gallery. All I simply did was install the dir listing module on IIS7 (need admin rights to do this) and then call it  via the web.config (just need access to your site's web.config file).  Last, I uploaded the pictures and turned dir browsing to on.

So far I hope that readers understand that IIS7 doesn't just allow you to post a pretty gallery up in no time. The purpose of the exercise was to show the extensibility so that you may shape IIS7 into whatever you need it to be.

Here is an interesting case that led me to write this post:

New Atlanta Communications  was able to to write a module that allows Cold Fusion to tie right into the core IIS7 pipeline for one of their main products (BlueDragon).  This allows Cold Fusion to plug in natively into IIS7 (just as ASP.net does).  They even went as far as writing an admin module. 

Read Vince Bofanti's blog to get the details.