Sorry, I think I was unclear. There’s no restriction on viewing open threads. But when you click on someone’s profile you can see that person’s entire history of past questions and answers—unless they have clicked the option to show their history only to their fluther.
Some months back, when the Q&A history capability was added to people’s profiles, some of us felt that it gathered too much information in one place for easy correlation. It felt too exposed. Others had no such concern. The compromise is that you can, if you want, limit that view of your own history only to those who are in your fluther. But anyone can still see all the posts in any thread.