A couple of key take outs -
''I have heard some marketers question whether adding symbols to subject lines will affect deliverability. In the research I’ve done so far, I have not seen that to be the case, and all of the examples showcased above were delivered to the inbox versus the junk folder''
''It’s also important to note that these Unicode symbols will not work in every email client. In addition, some of the symbols won’t render well on the small screen and will end up looking smushed and unrecognizable''
- Return Path
|Image from Alchemy Worx|
''Even if testing shows this to be effective at the moment, this advantage is likely to disappear over time as the trick becomes more prevalent.'
''Let’s not just do it for the sake of it, or because we want to cash in on the trend then move on''
- Alchemy Worx
Read more at Return Path and Alchemy Worx