Is it possible to have some data stored somewhere on your personal GitHub Pages?
For example a button that triggers a counter. When you click on the button, counter increments by 1. When other user visits that page and clicks the button, counter gets incremented by 1 once again.
So it would be a sum of all click across all visitors that would be displayed on the page.
Github pages only allow for static content, so you'd have to use something like firebase in order to get a database.