The delivery should be staged to balance the load on your servers, and the system should correctly handle undeliverable e-mail messages and vacation replies. It should be integrated with your knowledge base so your messages are archived there. Also, you must allow authorized clients to subscribe and unsubscribe from these e-mail lists on their own without having to contact your systems administrator. Regardless of how you decide to tackle an e-CRM project, remember that the system is not simply the collection of the different software packages. You will want to design your architecture with extreme care.
Scalability is the first issue to consider.
Making your knowledge base scalable may involve splitting it across multiple servers. Multiple replicated copies of the knowledge base should not be a problem to implement, but splitting the data across servers will require lots of effort to get it to work. Security is another issue. Your data should always be stored behind your firewalls, and your application servers that interface to the outside world would sit in the demilitarized zone. Make sure outsiders cannot break into your data servers.