What the heck is keybase ? I went to the website and it does not offer a clue about what this is or how it works. It says "download the app" but is not an app.

What the heck is keybase ? I went to the website and it does not offer a clue about what this is or how it works. It says "download the app" but is not an app. It says it's more than a website but does not seem to be distributed in any way. The fact that it failed at the most basic thing of actually telling what it is about, what it does and how would be good reasons to not use keybase.