Adestra recently did some research on subject lines length and content. I found some of the research interesting and endeavour to test a few myself.
- 6 – 10 word subject lines have high opens but not a lot of clicks, where long subject lines (over 16 words) help clicks and opens
- Avoid using B2B, business, industry, ROI, free and exclusive. However words with monetary symbols and phrases including news, profit, revenue, turnover, referral, acquisition, and deal have better click to open rates
- a subject line with 20 words is the optimum
- mentioning video will significantly help you
- avoid ‘free’ and ‘half price’, instead use ‘% off’
In their overview of the publishing sector, I found it quite interesting to see what content words had better open and click-throughs. The words which didn’t perform so well on click to opens surprisingly included newsletter, research, report, forecast, intelligence, issues, alert, and special. However the successful content based words were video, interview, bulletin and exclusive.