Special thanks to Marshall Cohen from MarsDesign.com for sending us this great troubleshooting article on Lotus Notes and HTML email:
Covers all those familiar problems with Lotus Notes: image borders, CSS, tables, etc.
If you have lots of corporate customers on your list, chances are a good percentage of them use Lotus Notes. You can download Lotus free at the IBM website, if you want to test email designs yourself:
Download Lotus Notes: http://www-306.ibm.com/software/lotus/