I like the fact that there is a good email product under Linux such as scalix which is one of the first ones trying to utilise the functionality of Exchange/Outlook.
I think where Scalix got it wrong is to try and push a product and which has limited functionality as an Exchange replacement and asking for $$$ similar to Exchange.
You need a stable product good market share, get the vendors to notice you either wite plugins for your product or give you access to their development platform.
As you push your product for an X price users have expectations. They expect the iPhone, Blackberry, WM 5/6/7 to work out of the box NOT using hacks or half baked solutions.
You need to go back and rethink your approach, you are pushing the community that has loved you so much AWAY.
You need to rething your pricing structure, allow small busineses to participate more and give access to pda type devices license access by user or pack.
Also if you want to penetrate the market your product HAS TO BE MUCH CHEAPER than Exchange especially since it does not come even close to Exchange's functionality.
You have to hit for numbers and I believe that is how you are going to make your money.
Thank you,
Steve