[TheOtherHobbes]

Trolling and sock puppet accounts etc were already popular on Usenet in the mid 90s.

Someone who knows more history than I do can probably take them a lot further back to (e.g.) public pamphlet debates in the 17th century. I wouldn't be surprised if there were Roman and Greek equivalents.

Anonymous independent-action-under-a-common-pseudonym has a long history in politics. The Angry Brigade and King Mob are two recent pre-Internet examples - from the UK in the 60s/70s.

Historically, Internet trolling is a lot more civilised than some of the things that used to go in previous centuries. Trolls may be rude to you on Twitter, and they may even dox you and cyber-stalk you. But unpopular people don't often have to face a lynch mob or a riot outside their front door.