When I first started my email marketing business five years ago the rule of thumb for the proportion of subscribers who read in plain text was 5-10%, based on various web articles I read.
Five years later things have moved on and more and more people are reading in HTML on smartphones or in webmail clients.
Does anyone know what proportion of subscribers are likely to be reading in plain text these days?
Hey again Julian, unfortunately we haven't been able to get reliable statistics for plain-text readership, largely because these opens can't be recorded. I'll follow up with the team now and see if there's a workaround here - there is a chance that we assign different tracking links for the HTML and plain-text alternative of a campaign. If this is the case, I'll do my best to dig up some stats for you.
Cross your fingers for me! :D