2D hierarchical discussions (reddit, email, etc) leave a lot to be desired on focusing conversation and easy navigation
Can allow single reply to multiple parents
Should be movable/zoomable like a third person RPG
Navigation potentially much faster than vertical scrolling since multiple types of interactions can be used to hop around
Oddly enough would have been good use case for vrml due to selectable text...but in this case, probably webgl or dom tricks (is there a good rust abstraction over opengl and WASM webgl yet?)...
DOM tricks w/ z index and sizing and fading would be kinda neat and still preserve text selection, links, etc
Each comment can appear as cube, or billboard sprite, or whatever
Entire thread can appear as just in floating space, on a set of topographical hills by popularity (responses on downslopes?)
Allows further down comments to appear in distance allowing you to see more of the landscape at once since depth can be used
Navigating from one comment to the other can use nav keys/touch or just clicking... clicking could do something like center the comment on the screen making it seem like the top of a pyramid you're looking down on from the sky with the rest appearing as downwards in background at differing depths (think how space-based RTS centers something you click on)
Using modern rendering allows all sorts of customizing such as adding a glowing effect to a popular comment down thread (even though it may be too small to read), making recent ones pulsate, etc
Sorting by highest voted becomes more interesting, because it's no longer limited to top-level highest voted, it can be highest voted at any depth in the thread (parents and children appear off of them in 3D)
Can even gamify interactions such as upvotes and downvotes
Should be simple, self-contained, framework-independent js lib (embeds WASM as necessary) so it could be used for anyone that has a discussion set formatted to a certain JSON structure