“…hashtags serve absolutely no purpose in email subject lines. In fact they may even hinder a recipient’s ability to search for your email.”

@Christophe_Rock

If you think putting hashtags in an email subject like looks cool, it’s not; and it also doesn’t boost open rates or improve conversions. Hashtags have their place on the internet, and so do trending words like fleek, cray-cray, and TBT (throwback Thursday) but none of them belong in your subject lines, and usually not in your email content.