In his Coding Horror blog, Jeff Atwood makes the case that online discussions should be flat rather than threaded. “Flat” means a discussion consists of a single linear chain of messages in chronological order. “Threaded” means replies can be inserted anywhere, so sub-discussions can branch off the main discussions, sub-sub-discussions can branch off from those, etc.

I have maintained the same position for years. Almost 40 years, in fact — I designed PLATO Notes discussions to be flat, and I’ve always argued that a flat structure is best for promoting group discussion because it most closely replicates the experience of holding a face-to-face discussion with a bunch of people. I allow that threading has some valid uses, particularly for tech support, question-and-answer sorts of applications where you’re not there to engage in prolonged discussions but just want to drill down to a specific answer as quickly as possible and leave.

Anyway, I appreciate Atwood’s post because he goes into the flat vs. threaded argument in more depth than I ever have. I agree with all of his key points:

• Browsing a tree is complicated because you have to constantly think about what level you’re at, what’s expanded, what’s collapsed.
• Replies can arrive any place in the tree any time. How do you know if there are new replies? Where do you find them?
• Indented replies to replies to replies push the discussion off your screen.
• Replying to a reply gives you the impression you’re only talking to that person, but in reality you’re talking to everyone.
• Scrolling down is the most natural way to get through a discussion. Having to collapse dozens of random tangents is too much work.

Here’s what I’ve had to say on this topic in the past.

Read Jeff Atwood’s full blog post.