Can someone explain what 'visibility' is (without an algorithm) Thanks!

Visibility - is the average position of a website in the search results by all your keywords expressed in a percentage. It is a general definition. In Rankinity you can tune the visibility formula by assigning weights for the keywords. So we can imagine the website as a tree in the forest, the Rankinity service as a camera that allows you to monitor your website visibility via the lens, and the keyword weight can be thought as the focus setting for the camera.

If you have any additional questions, please feel free to ask.