Well, to be fair London is freaking huge. Depending where you live in London you mileage might vary. But now that you know about the "orange card" you might be able to notice it around you.

There are ads on the tube now so it's harder to not notice today. Before it was just the hot coral card that was advertising it and easy to notice, especially so when you have one. I remember last year when it was cool and special to see others use it, now it's just par for the course here in London.