Earlier quoted context omitted.
A linear forum compared to a nested forum is like cutting off part of your brain. You have to expend brain power sorting out multiple conversations occurring in the same sequence. The quoting mechanism is an attempt to unbreak the linear forum, but it's a kludge. Linear forums are a cacophony of conversations intermixed. Deep conversations die early on linear forums because they are too hard to follow. You will find…
The downside is that it's nearly impossible to go back to a thread and continue where you left off. With a linear thread, you can go back to the last post you read and continue from there -- with a fully threaded forum, I basically get one pass at the comments and then can never view that page again without huge effort to reconstruct my position.
edit: In yesterday's discussion I posted some advantages of a discussion system based on tree structure https://news.ycombinator.com/item?id=5175660