I have some tangential experience here in analytics and advertising, including non-ad social campaigns, and from what I've seen the reporting in the press is likely just the tip of the iceberg. Additionally, much of the focus on the advertising element has distracted from broader and more powerful influence campaigns that operated outside of ads.
From an advertising performance standpoint yes, lookalikes and segmented email lists might perform best on the basis of maximizing engagement, shares, etc. that traditional reporting would suggest. But for a political campaign, enhancing the precision of issue-based messaging to target specific groups should theoretically have yielded gains beyond what the FB algorithm would optimize for – which would likely be more generalized based on in-platform behavior, and muddied by swaths of broadly viral content. While the desired signals might lie somewhere within Facebook's black box, I doubt that the algorithm is generally optimized for this type of political work, when FB's real money comes from driving product sales, signups, etc. In the cases of these political campaigns a lot of this content extended beyond spin to blatantly false information (i.e. made up / completely fake news, inflammatory memes, etc.) – therefore the variance in messaging could be unfathomably massive, limited only by the ability to generate huge amounts of content, which is where content / troll farms came into play.
And advertising aside, the Senate intelligence reports from a couple months ago suggested that the most powerful and far-reaching operations run by CA and similar parties were not based on advertising, and moreso around Facebook groups, Twitter bot / follower networks, and Instagram influencer spheres – recruiting real people into them, then propagating information within (e.g., a 2nd amendment group, run by false avatar accounts aligned with this voter profile, recruiting similar actual users in, and then propagating the desired information within). I've personally seen prior examples from 2014 of these types of mass influence campaigns, namely in the 2014 Senate race in North Carolina, where the seat was flipped to Tillis (R) from the incumbent Hagan (D).
If they had account information / emails, psychographic data, voter rolls, and were operating across platforms – the richness of the data would dictate how far you could go with it. According to the Senate report many of the hired trolls maintained multiple accounts across multiple platforms, were given marching orders each day for messaging, and quotas for performance. Match that with sheer manpower to create content to feed across these platforms, and enough horsepower on the analytics side to optimize based on performance, and you're staring into a frightening abyss.
We'll likely never know how far this went, but based on the data points I've seen from my own work and various reports on the CA / Russia campaigns, I see no reason why something this powerful couldn't exist with enough data, and enough money to put it to work.
The senate intelligence report is essential reading on the topic: https://www.intelligence.senate.gov/sites/default/files/docu...