A friend of mine really likes using Joomla as a base for his websites. He also likes the power that Asp.Net has and can code in VB.Net.

He wants to use Joomla as the "Master Page" and Asp.Net/VB.Net/SQL Server to handle the main business logic of the application. He is planning on using the Joomla Wrapper Module (an **IFrame**, [joomla modules](http://help.joomla.org/content/view/1983/278/)) to integrate the ASP.Net into the Joomla website.

Joomla will be able to handle the security (users,roles,registration), menu (based on roles), static content (e.g. About Us page) and it will pass an Encrypted Username & Password to the Asp.Net web page ([example here](http://mtpamir.wordpress.com/2009/07/21/how-to-pass-joomla-1-5-parameters-to-wrapper-page/)).

The goal of the website is to allow users to register & subscribe to a (free or paid) service where they will be able to customize content and download it as a file.

What disadvantages are there when doing this? Are there work arounds?

Some issues that I can think of are:

1. Links clicked in an IFrame won't change the browser's url which means that you can't bookmark pages and they aren't in the browsers history.
2. If Asp.Net has to know the users/roles (which is very likely) then it would have to access the Joomla database or keep its own user table which will have to be in sync with Joomla's users.

EDIT:
I would never build a new website this way, but I was looking for concrete points to convince my friend that using Joomla and Asp.Net together isn't a good idea.