This! So much this!
If you want to test how effective things are, always make A/B tests.
And as stated before 8% click rate is pretty impressive.
Re:Ask HN: Why do newsletters not work?
by samayshamdasani on Monday December 05, 2016 @09:35PM
(#13111820)
Good point - will test out on the next email
The only emails I've ever received with emojis in the subject field have been spam. But, maybe I'm not your target audience. You could try split testing this.