I've see frequently (and have documented) numerous cases of ads implying that a famous person has died (e.g. Sly Stallone, The Rock, Lamar Odom, Colin Kaepernick), luring clicks for details.
But what really disgusts me is the "Suggested Post" mechanism. In the past week alone, I've had "Suggested Posts" from people selling obviously counterfeit merchandise and sites that claim to be the "Official NHL/NBA/MLB Store", when they are not. And these include plain text that should be simple to parse and check, if they cared. (A more complicated strategy to catch is when the bogus claims are only in text within the ad image, like the oft-posted phony Ray-Ban Official Site.)
And Facebook (and especially the ad network who made the ad) makes money for every sucker served.