Your question is Low-Level Design of Forum System. Take a moment with it on the right.
Talk me through your thinking if you like. When you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes).
Do a LLD (low-level design) of a Forum system which takes in posts and comments.
Asked in the technical interview stage. Asked in an AWS Embedded Firmware development interview even though the posting was about BMC firmware and Linux drivers; the candidate says it needed data structures such as hashmaps and priority queues.
Address the core entities, APIs, storage, comment threading, ordering, voting, moderation, and failure handling. Explain where an ML classifier could support spam or abuse detection without obscuring the low-level design.