I heard it back in 2011 where in there was a huge hype of mining Bitcoin using GPU's and there were numerous facebook groups where they posted they rigs and also had many tutorials for other to follow or even customize their rigs in order to work better.
I heard about bitcoin talk 1 month ago from my friend , he told me about how to work in bitcoin and share some video about bitcoin talk.
I heard bitcoin in year 2015 to my classmate in our classroom because they talking about bitcoin. My classmate endorse bitcoin to my other classmate on how to use it and how much they earn in bitcoin.