Physics Forums is a big place and it's sometimes difficult to find those threads that haven't received a response yet. I think we can all agree that every thread deserves to be responded to in some capacity. That is what helpful and friendly communities do. Back in PF 3.5 we had a link that listed the unanswered threads. That functionality is now back in PF 4.0! The Unanswered Threads link is located in the Forums navigation drop down, right below New Posts. The list by default shows the last 5 days worth. There is a link at the top right to push it to 7 days. Or you can quickly get there using this link https://www.physicsforums.com/unanswered/threads I should also mention that there is a trophy awarded to those who are often the first to respond to a thread. Thanks!!