Suggestions for thread types:
Generic
"extras" data json field for storing data subjective to only that thread type
Bug Threads
Custom fields addable via ACP stored in the extras field. Can be used for revision logging, version tracking, etc.
Anonymous threads
Post anonymously to the community. Do not reveal identity anywhere. Admin can see identity if required.
Competition Threads
Entry question.
Replies are answers.
Detect replies that are the correct answer.
Pick a random winner.