It's not a goofy idea. It's a big reason why I'm
not a fan of long project / build threads. Good info gets buried.
I went back and added a chronological index (summary, really) to post one of the
ForkenSwift thread, but it took a fair amount of time. That said, it also made the thread vastly more useful to me - I've gone to the index many, many times to look up specific things.
Indexing all long threads would be amazing, but I bet most people don't see it as worth the trouble.