Carey,
This forum software tracked where people have been the same way many other forms did for a long time. It was done through a bizarre algorithm which I never understood that seem to be based entirely upon the last time a user visited the site.
Fortunately this site is about software engineering and the moderators are software engineers. Jeanne modified the software so that a person could activate a feature that would use a different algorithm for tracking where you have been. I activated it for my account. I think it is 20 times better than the original algorithm.
Jeanne warned that this new algorithm is pretty resource intensive. We should go easy on using it or it could overwhelm our server.
More recently, devaka developed the pie feature. I asked that the resource-intensive
thread tracking feature be moved into the pie options.
Is it possible that you turn this feature on and enjoyed it and then the feature became available to pie users only?