Stupid question #1A

Trolling online. Where does that term come from? Trolling like a fisherman? Or like the big ugly monsters?

I always thought it was the monster because you can be called a troll. I don’t know what the fishing thing is.

Origin and etymology
There are competing theories of where and when troll was first used in Internet slang, with numerous unattested accounts of BBS and UseNet origins in the early 80s or before.
The English noun troll in the standard sense of ugly dwarf or giant dates to 1610 and comes from the Old Norse word troll meaning giant or demon.[18] The word evokes the trolls of Scandinavian folklore and children’s tales: antisocial, quarrelsome and slow-witted creatures which make life difficult for travellers.[19][20]
In modern English usage, trolling may describe the fishing technique of slowly dragging a lure or baited hook from a moving boat[21] whereas trawling describes the generally commercial act of dragging a fishing net.
Early non-Internet related slang use of trolling for actions deliberately performed to provoke a reaction can be found in the military: by 1972 the term trolling for MiGs was documented in use by US Navy pilots in Vietnam.[22]
The contemporary use of the term is alleged to have appeared on the Internet in the late 1980s,[23] but the earliest known attestation according to the OED is in 1992.[24]
Another claim sets the origin in Usenet in the early 1990s as in the phrase “trolling for newbies”, as used in alt.folklore.urban (AFU).[25][26] Commonly, what is meant is a relatively gentle inside joke by veteran users, presenting questions or topics that had been so overdone that only a new user would respond to them earnestly. For example, a veteran of the group might make a post on the common misconception that glass flows over time. Long-time readers would both recognize the poster’s name and know that the topic had been discussed a lot, but new subscribers to the group would not realize, and would thus respond. These types of trolls served as a practice to identify group insiders. This definition of trolling, considerably narrower than the modern understanding of the term, was considered a positive contribution.[25][27] One of the most notorious AFU trollers, David Mikkelson,[25] went on to create the urban folklore website Snopes.com.
By the late 1990s, alt.folklore.urban had such heavy traffic and participation that trolling of this sort was frowned upon. Others expanded the term to include the practice of playing a seriously misinformed or deluded user, even in newsgroups where one was not a regular; these were often attempts at humor rather than provocation. In such contexts, the noun troll usually referred to an act of trolling—or to the resulting discussion—rather than to the author.

They do mention the fishing thing.