Earlier quoted context omitted.
Intent is huge. I've never been one to click on Google Ads except in real rare instances. Only once I observed my mom using Google did I realize the full value of intent and google ads while searching. She wanted to watch an episode of The Good Wife that she had missed so she searched in the Safari omnibar for "watch The Good Wife" and the first div under the search bar is an ad to some site that was not CBS that had…
Facebook has ads that people like your mother will think are from friends. If users can't tell the different between Google Ads and search terms (or between CBS and a random site), they're unlikely to distinguish between newsfeed updates from friends and paid ads. You're right that that's totally different from intent. But it's valuable for brands which spend billions [1] per year on exposure-focused ads, like produc…
That's a big assumption to make. The bar is low for search results because they have no personality.
For friends -- we know our friends. They have a distinct personality. Ads disguised as messages from friends could have a negative effect because of this dissonance.