There's even a dedicated website, hashtagonamac.com, to remind you of the shortcut. The problem is worse outside of the US, because on international keyboards the hash symbol isn't simply Shift+3.
But a new Kickstarter campaign is aiming to change all that. HashKey is a USB peripheral that adds a dedicated hash key to any computer.
The campaign is looking to raise £15,000 to develop a range of the external keys.
And in case you're worried about the authenticity of this particular hash key, don't fret. Chris Messina, the inventor of the hashtag, has called it "#awesome."