What else can one click prove?

from here and here (image sources one and two)

It's amazing to me how much heavy lifting a single click can do. It can prove your identity, your humanity, that you read and agreed to the terms and conditions, etc.

I Can't See The Difference. Can You?

from here (source image one and two)

There's a reason they're so similar - they both do the same thing. Facebook is tracking you where ever you go, and sites that use that "like button" are helping them.