There was a startup in my region who got popular with the simple idea of having a website/service that manages simple events, like talks, presentations etc.

I think it started with mostly students using it because there used to be a lot of university-related events like these, and eventually they’ve become the standard platform for that, at least in the State. It was all pretty simple, it managed payment etc. and you’d get a QR code by email or in the app that could be scanned in the entrance.