The blog post includes a testimonial from Content Director, Anne Holland that shorter subject lines for one of the Marketing Sherpa newsletters "invariably got better open rates."
One online retailer that I've observed often "goes short" is Urban Outfitters. Here's a screenshot of the last few months' of subject lines. Of course, if they are split testing subject lines, it may not be a perfect record of their campaign. But one subject line in particular may just be the world's shortest subject line: A+
Assuming Urban Outfitters is doing rigorous testing, the trend I see in my inbox indicates it's either working or test results haven't been dismal enough to abandon the strategy, depending on how long the testing period is.
I'm not convinced the copy is the most compelling..."Naming Names" and "Turn It Up" don't give me enough information about the email content to motivate me to click on the offer. I chuckled at the "Aloha, Mr. Hand" throwback, but wonder how many of Urban's current target demographic could place the movie it's from. However, the unconventional titles are consistent with Urban's image. So long as the customer expects attractive offers after the click, this strategy could work well for U.O.
To truly get an A+, Urban Outfitters could work on their pre-header text and take advantage of marketing within it, rather than showing Gmail and other email users "Having trouble with the email below..." messsage every time.