Litmus recommends around 50 characters. Yes Lifecycle Marketing says emails with subject line up to 20 characters have ethe highest average open rate, unique click rate, and click-to-open rate. An analysis from Retention Science found that subject lines with 6 to 10 words results in the highest open rates. And Return Path advises using 61 to 70 characters.
AWeber finds a healthy balance between ease of use and robust functionality. There are some nice features — particularly in the autoresponder realm — but navigation is intuitive enough that I was able to perform basic tasks without looking up tutorials. When I did find myself at a loss and turned to the online help resources, I was quite impressed with the range and scope of guidance available.
Think about implementing referral links to incentivize your subscribers to spread awareness about your brand, too. Referral links allow your current customers to promote trackable links for your business. In exchange for sending new paying customers your way, you can give them incentives like discounts, coupons, vouchers, cash, prizes or redeemable points.