One of the things that people still hang on to as a metric - for whatever peculiar reason - is how many 'likes' they get on their Facebook page(s) - a flawed metric, to be sure.
Engagement in social media is always more important than a snapshot of people who 'like' something.
So you can advertise on Facebook and get likes - but those likes do not translate to engagement.
The page discussed in the video is something along the lines of a honeypot, and the theory put forward in the video is that people in click-farms (places that get paid to click 'like') click the ads to get past algorithms that might spot them, thus causing people to spend ad money to google while the click-farms make nothing.
That's a nice way to look at the data. A less nice way might be to say that Facebook might be paying the link farms less than the revenue that they generate from the ads to click the ads. That's speculation, but it also fits the data.
Either way, the net result is the same: Facebook ads aren't that useful - and it does make one wonder whether other paid social media exposure is worth it as well.
If the metric is the amount spent versus the number of 'likes', followers, et al - it's a flawed metric because you can't gauge whether you're actually getting exposure. The only real metric is engagement and interaction - something most people impossible to measure. But you can measure engagement in various ways.
Counting the number of shares/retweets is one way to measure engagement. Another is mentions, where someone mentions you - and lastly, comments on things that are posted, conversations that are had, etc. The unfortunate part of measuring engagement in these ways is that it's quantitative and omits qualitative.
Qualitative, of course, is much more tricky.
So save your money and grow your social media presence organically. It's 'slower', but if your social media is important to yourself and/or your organization, don't think that the number of likes/followers someone has is worthwhile. It isn't. It's about interaction, engagement and community.