This is mostly useful for large forums, right..? On a forum like Wedge.org, you can simply have a look at the numbers next to the latest topics, in the homepage..?
@Nao I think it's more of a trending topics kinda deal where as its displaying the most popular topic of say the day or week or whatever timeframe vs. say the most replied to topic overall. At least thats what i gather from it.
@live627 I like it, why not be cliché and call it trending topics :P