I would have thought that invoking a C compiler would be a solved problem. Looking at Rust's cc crate there's a remarkable long tail of corner cases to fix.
Exotic CPUs, microarchitectures, compiler differences, operating system differences, etc.
The line between 'group chat' tool and 'web forum' seems increasingly blurry. What are the essential differences?
The ability to edit? "$USER is typing" information? Threading? Simply the culture around the tool?
The level of sophistication in tool-assisted speed runs of video games is really impressive.
"Both bosses are incredibly annoying: they are liable to desynch on any changes to earlier levels due to differences in the RNG." https://tasvideos.org/2416S.html