I recently signed up to receive the TechSoup.org email newsletter, and was pleasantly surprised at how well-designed their plain-text email is. It’s easy to get caught up in the razzle-dazzle-jazzy-fun of HTML email, but plain-text is often just as good; sometimes better.
Our favorite feature of "By The Cup" is their "Off The Cup" section, which highlights member-submitted soup recipes. It’s fun, interesting, and brings some personality to the newsletter. TechSoup also includes helpful hints and resources, plus links to active discussions on their site.
If you’re sending very frequent emails, such as for breaking industry news, or special offers to customers, you should strongly consider going with plain-text, because it’s less "weighty" and easier to skim and scan through. Think daily newspaper (black and white, fewer pictures) versus monthly magazine (slick paper, lots of photos and ads).
The only downside (for marketers) of plain-text email is that you can’t track open rates like you can with HTML email. You can track clicks with plain-text email, but be aware that tracking clicks usually means your URLs will be altered with tracking code, so test before you track. Why not shoot for the best of both worlds? Design an HTML email that looks like a plain-text email, is easy to scan, "lite" on graphics, and has all the tracking you need?