You can also see the popularity of threads through time. All Time is good, but you can see the most popular threads of the last day, or the last week.
It's worth noting that if you chose "last day", as an example, all you are going to see are threads created
in the last 24 hours. You will not see last day replies to threads that were started 2 days, or two years ago. Honest. Unless they've changed the system again, that is.