&gt; It&#x27;s mostly done sarcastically, though when you do it all the time, is it really sarcastic?<p>Anecdotally, it seems that this is how a lot of new phrasing is spread. It starts off funny, then ironically as an inside joke, then it&#x27;s just wrote.<p>My little sister started tapping her index and middle fingers together to make a hash symbol while saying &quot;hashtag [whatever]&quot;. Started out as a joke, making a bit of fun of some tv show or something and at the same time pointing out that she &quot;got&quot; the reference... and before she knew it it was second nature.