The OpenBSD’s mailing list page netiquette section is excellent. It is a distillation of how to communicate online, i.e.:
- Plain text, 72 characters per line [or simplest formatting available]
- Do your homework before writing
- Include a useful subject line [or headline]
- Trim your signature
- Stay on topic
- Include important information
- Respect differences in opinion and philosophy
Using only plain text is extreme outside of email. But, the idea that formatting should not get in the way of content is good. Know what you are talking about. Help others to understand. Give them all the relevant information. Trim out anything that does not move the discussion forward or is confusing. Treat everyone with respect.
It’s good advice for any kind of communication and for life. It’s relevant to writing an email, a newsletter, a blog post, an article or anything else you may do.