Fantastic tool and really damning indictment of how we’ve just defaulted to letting third party tracking seep into just about everything we build online (nice behind the scenes writeup about how Blacklight was built). I have intentionally avoided embedding a single tracker on this site, but as of today (22 September 2020), there are three third party cookies on my homepage because of embedded YouTube videos. I’m reminded the original spec for browser cookies said pretty explicitly that third party cookies should be rejected by default, but Netscape and IE simply failed to implement that provision. I’ll also note at the time they were ignoring their own spec, Netscape was managed by future-Facebook board member Marc Andreessen; and the one browser that seems uninterested in implementing third-party cookie blocking today is Google’s Chrome.