I've seen many posts about keeping your cards close to your chest, being mysterious etc.

I am wondering to what extent you do this. I had a successful date where I revealed literally nothing about myself and they were super keen for a second. They were pretty boring themselves and the conversation wasn't great, it took a lot to keep it going and keep them floating in their happy solipsistic bubble. Second date ended abruptly which was fine, I had lost interest and was just using it to experiment, but I wonder if them knowing nothing about me contributed. Perhaps I should reveal a little bit, without elaborating, in future. I am not sure and interested to hear people's thoughts.