> However most ad tech companies including I believe Google and FB are very leery of doing this "Harry" type of stunt and arrange data pipelines in a way that t

> However most ad tech companies including I believe Google and FB are very leery of doing this "Harry" type of stunt and arrange data pipelines in a way that this cannot be done at any aggregation less than a few hundred IDs I would be interested to see any sources about this (I’m not questioning what is said in the comment, just genuinely curious about this topic)