In addition to the standard way of viewing messages inside the forum, FUDforum 2.3 supports a tree view, which builds a tree of messages akin to the one used by the newsgroups.
Example 2.1. Sample Tree View
[*] Main Message [-] Reply To: Main Message [+] Reply To: Main Message [+] Reply To: Reply To: Main Message [-] Reply To: Reply To: Reply To: Main Message [-] Another Reply to Main Message