I am pretty sure that I caught on when all my friends were talking about it, and this was when the first one came out. It was just a progression from there.
I found out about Borderlands 2 when my favorite Youtuber did a let's play of it. It looked pretty boring at first, but then I started thinking " Huh, I could actually play this". And i did.
My friend recommended it so we can play it together and we had a blast. It was pretty popular at the time and I knew the name, but didn't know what it was about. A lot of youtubers made videos about the game and steam was having a lot of steam sales so it is hard not to hear about this game.
I agree it is hard not to hear about games but I have found myself a victim of just too many to keep track of. Seems to be happening more and more these days and I can see it not ending anytime, which is good don't get me wrong.
I'm the opposite. It seems like with each year there are less and less games I'm interested in, probably because I'm an old school gamer.
I've found out about it when I was looking for a low-medium spec game and it popped out of a steam sale. It was an instant buy because of the steam user ratings. Everyone liked the game and then after I finished it, I played all the Borderland games.
I think for me it was through the online video streaming sites I guess. Some sites were releasing the trailer. And it was a good idea to watch some of those in that case. I am sure many people would love watching this.