I have seen many threads where awesome community develop their own expansion cards or similarly technical projects. They tend do get a lot of feedback from a lot of people or sometimes it is almost a development process happening over the course of the thread.
The problem is, if you happen to find the thread a while after it has been created and active, you might have to read through 100+ posts to understand the current state of the project or the conversation in general.
It would be helpful if maybe the owner of the thread or moderators could pin a post at the top/bottom/to the side of the main thread. It could be used for an overview or current development status or feature set of the project in the thread.
Such a function would also be helpful for solved/responded community support threads or honestly, probably all topics could make use of a pinned comment feature.