I built a very simple website [0] for playing poker. The idea was that people can play poker in person without chips or a deck of cards. I had also planned for more features like hand history. But it didn't catch on and number of users is not growing.

I've also learned that if your project has anything to do with the following topic, you can forget about online advertising: poker, blockchain, porn (probably). I did not know this and had incorrect assumptions about promoting the project.

0: https://playcards.live