In 1980, I wrote the roleplaying game "Call of Cthulhu".
At that time, every single person I knew who'd heard of Lovecraft did so because I had told them personally. Lovecraft was an unknown. A vanishingly obscure pulp author.
When Chaosium asked me to write the roleplaying game, we expected Call of Cthulhu to be a real niche produce. To sell a three or four thousand copies tops to the few hard-core Lovecraft fans in the world, and then go out of print. I put my heart and soul into it anyway because I loved Lovecraft so much, and I wanted to make sure my few fellow Lovecraftians would have the best game possible.
Well, instead of the game being based and fed by Lovecraft fans, instead the game PROMOTED Lovecraft and spread knowledge of his works everywhere. It quickly became Chaosium's best-selling product. Every gamer knew about it, even if they didn't play it.
My proudest achievement is that I have had literally thousands of people walk up to me at conventions and tell me that they read Lovecraft after playing Call of Cthulhu. Others (three times tearfully) told me that they were so excited to see that someone else knew about Lovecraft. This last event is now rare, because now everyone knows about Lovecraft.
I am so glad I have been a tiny part of bringing cosmic horror to so many.