I looked up fingerprinting on Wikipedia, although my understanding still isn't great. I get the impression from that article that it's similar to the MD5 hash that files use to ensure that the file didn't become corrupt when it got downloaded. What does fingerprinting mean as a web user though?
The social media pixels (before social media existed) were called spacers IIRC. 1x1 pixels used inside of emails that would "phone home" when the email message has been opened. If there are spacers on this forum or on Amazon/eBay etc, I think something like NoScript can be used to whitelist primary domains such as Facebook (if you're actually on Facebook), but to blacklist Facebook as a secondary domain, so if you're on OcUK and the forum's source code references Facebook in numerous places, then that can be blocked by NoScript.