DNS is a complex system. What you have read so far is just the tip of… the tip of the iceberg. I hope it is enough, however, to help you decide if any of these “DNS hacks” could be useful for you, and show you the road to implement them:
Just a few notes on the purpose, structure of DNS, with some really basic configuration procedures and tricks for DNS on Linux
(update 2010/05/29: here’s another article about VPES legal, management and economics issues)
The way email is normally used today has several serious limits that I recently explained in another article. I also pointed out that one of the biggest obstacles to personal email management is lack of user demand for Virtual Personal Email Server (VPES) software and hosting packages. A VPES may run into any computer in your home or in some external datacenter, but that is another issue. Here I only want to look at the software side, that is to explain what are, in my opinion, the technical requirements and features of the perfect VPES. You are welcome to add your own in the comments and, if you’re a hosting provider already offering VPES, to add a link to your offer in the same way.
Taking full control of your own email, that is running your own email server, is a must if you really care about privacy, security or maximum customization.