[Xeroday]

Was on incognito and wondering why I didn't see any red squares...

[mataug]

That is, I am guessing, because there aren't any re-marketing cookies,history and other markers when you open the page in incognito

[ZoF]

No, it was because incognito tabs don't have access to browser history.

This web-app's functionality is based entirely on browser history and has nothing to do with 're-marketing cookies' or other 'markers'.

Not to mention that the parent commenter clearly understood this fact.