The email that is sent to the mailing list on Technometria is generated automatically from the RSS feed for the "Newsletter" category on my blog. As I write my blog, I just properly categorize anything I want to be sent to the newsletter and it happens. The magic is a little python program called rss2email.py by Aaron Swartz. I modified the program to make it usable for my newsletter application.
The problem is that the program was designed for one feed and one email address. I've wanted to do regular mailings to the UtahPolitics.org mailing list in the same way, but that would require rewriting the Python script in some pretty serious ways. I decided that I'd rather rewrite it in Scheme, so I did. I've described the program here.
Right now, making it work requires more knowledge of Scheme than I'd like. For example, the configuration is stored in the program as an assoc list. I'd rather it be in an external file that people could edit and use. Also, the GDBM extension I use is not "just there" like the other libraries are.
Even so, if you're interested in making it work on your system, you would need system admin skills more than a knowledge of Scheme. installing MzScheme is fairly straightforward. So, if parentheses don't scare you too much, give it a go. I'm happy to answer questions about it.