The first job of most algorithms is to keep us looking at social media. This means showing posts we are more likely to engage with by liking or commenting. This means showing posts that cause us to click through and look at further posts. The longer a user spends on social media the more ad revenue they generate.
Most algorithms are centered around creating this kind of addictive engagement. (Including things such as offering scary stories late at night and news segments in the morning.)
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