This is funny, but what's the meaning? ¯_(ツ)_/¯
Usually the most popular threads have introductory content for new members, broadcast important events, or reflect the most common interests of the forum members. So new people can easily find these threads, look through them and quickly get an idea about forum purposes, events, rules and customs.
If there will be non-informative popular thread, it may somewhat confuse new people and make it a bit more difficult for them to quickly find important ones.