I would say it should be a special type of front end format for this brain in which child thoughts should appear in chronological order one under the other.
The topics and subtopics (categories and subcategories) should be types (one parent only for each subcategory), but the richness of the underlying relations will be found in the tags (as per V10 in which tags are exactly as thoughts). So if you want to see more relations you just choose the tags attached to any post and you will get into other related posts easily. Tags for me in this sense will be like the gateways into other regions of the "Forum Brain"
Supported videos include:
Please paste your code into the box below: