In mythology, a large ugly creature; in internet culture, someone who deliberately provokes others online. As a verb, to fish by trailing bait or to provoke online.
From Old Norse troll 'giant, demon'. The internet sense comes from the fishing term 'trolling' (trailing a line), metaphorically describing how online provocateurs 'bait' responses.
The transformation from Norse mythology to internet culture is fascinating - both versions involve creatures lurking in hidden places (under bridges vs. behind screens) who emerge to torment travelers. Internet trolling exploits the same psychological vulnerabilities that made bridge trolls effective in folklore.
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