I know that this post is again related to SAAS (Software As A Service). Actually, it has some relations with APEX for since we are mixing both.
Apex is a good development tool for SAAS. Not just because it is secure and scalable, but also because the web applications are generated dynamically. So , customizing each pages for each requirements is easier with APEX than using other traditionnal development tools.
Anyway, the other reason that I blog about SAAS again is that I am preparing for my ODTUG presentation about building multi-tenant SAAS applications with Oracle Application Express.
Here is a good PDF document listing the top ten DOs and Don'ts when providing SAAS. We have been working with our Adsum SAAS product for over 5 years now and I find that this document is very accurate.