I've never actually seen anyone do the hashtag thingy with their fingers when talking in person, and for that I count myself lucky. Maybe because I make it a point not to hang out with douchebags? I don't know. (I did see a video once where teenagers were critically analyzing Robin Thicke's "Blurred Lines" video and two of them did the little hashtag finger thingy.)
There's a new video making its way around the Web in which Jimmy Fallon and Justin Timberlake show everyone exactly how douchey people sound when they add hashtags to everything they say. Consider it a public service announcement. The more you know.
(Spoiler alert: there's a guy in a Hall & Oates shirt at the end, and it's pretty fantastic.)