Trolling is a fishing term. The sense of 'internet troll' is based on a fishing metaphor. Trawling and trolling are slightly different fishing techniques. Both

Trolling is a fishing term. The sense of 'internet troll' is based on a fishing metaphor. Trawling and trolling are slightly different fishing techniques. Both are ways to catch fish from a moving boat, but trawling involves dragging a net, while trolling means trailing a baited line.