Promotional hashtags are becoming more visible offline as well. And every now and then you'l see one that isn't trying to sell something, which shows just how pervasive they're becoming.
I saw an example of this recently in Fremantle. It was a play on the meaning of the #JeSuisCharlie hashtag that took off in the wake of those terrible murders in France.
Hashtags are often "hijacked" and made to mean something different to their original meaning online. And as this example shows, it can happen offline too.
If you want to check it out yourself it's on the western side of the Wool Store building in Fremantle, not far from the train station.