EmailResource has been designed to take any MODX resource (simplistically, any page you can create) and sends it to an email address - that is, it sends a single email only.
The value of this is that it allows you to largely automate email newsletter creation. You can make a resource which contains the introductory text of your last six articles, or all your articles since you sent the last newsletter, or whatever you like. You can use HTML markup. You can create a CSS file, and EmailResource will take that CSS and turn it into inline styles, which are required for email that will display well in a wide variety of email clients.
Why doesn't it send the emails itself? Because bulk emailing is harder than it looks, and because you can use MailChimp to do the job very effectively.
If you're going to send a lot of emails, and you want them to get through, you need to set up:
- Reverse PTR records
- DomainKeys
- SenderID
- Bounce handling
See
http://www.codinghorror.com/blog/2010/04/so-youd-like-to-send-some-email-through-code.html by Jeff Atwood, who is no fool.
To make all this work you will need to have a co-operative ISP. Most ISPs hate bulk emailers, for obvious reasons.
Hence the attraction of an email bureau like MailChimp. They have all this worked out, including the extra-tricky bounce management piece. MailChimp is particularly appealing because they are cheap, and because they offer "email beaming" - you send an email to a special address, and they turn it into a ready-to-send email campaign.
Email creation is best done in MODX. But for many people, email delivery is arguably best handled by an outside bureau.
And if you want to send the email yourself, and have figured out a way to handle the bounce management and configuration issues? Try the DitsNews extra:
http://modx.com/extras/package/ditsnews