"What is an aha moment? It's a moment of clarity, a defining moment where you gain real wisdom - wisdom you can use to change your life. Whether big or small, funny or sad, they can be surprising and inspiring. Each one is unique, deeply personal, and we think, worth sharing."

Another word for that is "light bulb moment ". When you don't catch the meaning (you are "in the dark") for a long time and suddenly you discover what it's all about (someone switches the light on). I didn't know "aha moment" is used outside of German.

It is the time when you express your joy at the victory of understanding by saying "aha!"

expressed of sudden discovery

We've been enjoying a revival of the 1980's culture which includes the awesome work of Paul Waaktaar-Savoy, Magne Furuholmen and Morten Harket. Find your a-ha moment here: http://www.youtube.com/watch?v=djV11Xbc914 ...seriously though... ;) When we realise or discover something, it's common to exclaim, "a-haaa!!". So the exact moment that happens is known as an "aha moment". If we are collectively going through an "aha moment" that means we (as a culture or group) are realising and discovering many things.