Is plain text just plain best?

I have a colleague who regularly uses email to prospect for consulting work. She sends out plain text emails, and swears by the results.

Every now and then the 'text vs HTML' debate is re-kindled. Just when is it best to send in plain text?

Let's consider the benefits:

• no worries about rendering or image blocking
  
• good delivery rate: less likely to fall foul of filters
  
• may be more likely to get read, doesn't look like a 'marketing email'
  
• the 'low tech' approach may be better received by some target audiences

But what are the cons? Here's what comes to mind:

• no way of tracking opens
  
• trackable links can be very long and in some email clients this will cause them to break
  
• with no graphical content the copy has to be excellent
  
• for some businesses the images are crucial (eg mail order clothing)
  
• lack of visual branding may make the message unmemorable

My consultant colleague only sends out small numbers of highly targeted emails, and I would guess her high success rate is down to relevance and timing, two of the most important factors in any email campaign.

For the majority of clients I still recommend HTML, but with the usual caveats: don't rely too heavily on images, include a link to a web version, offer a plain text version for those who prefer it and send your campaigns in multipart format, so that the text version is delivered if HTML can't be displayed.

Image blocking: what you can do

The other day I received an email which illustrates perfectly the problem of image blocking. Here's how it looked before and after I turned on images:

Default view - click to enlarge

With images turned on - click to enlarge

To make matters worse there was no ALT text for the images, and the link to the web version actually wasn't a live link.

A number of significant email clients now have images turned off by default: AOL, Googlemail/Gmail, Windows Live Mail, Outlook 2007 and some versions of Outlook Express, to name just a few. In most cases, the recipient is in control and can enable images if he or she wishes to - either on an email-by-email basis or by changing the setting.

So what can you do? As usual, it's damage limitation:

• Test how your HTML email appears with images turned off
  
• Add a text-based link to a web version, at the top of the email
  
• Use ALT text for all images
  
• Do not use images for important content like headlines and links
  
• Ask recipients to add you to their address book

Regarding the last point, don't assume people know how to do this. Usability research suggests that if you give people instructions on how to add addresses to their address book or trusted sender list, it greatly increases uptake (Marketing Sherpa email Benchmark Guide 2007). This might mean setting up a page on your website with basic instructions and screenshots of the major email clients.