We measure popularity by how many unique clicks each listing has had in the last 7 days. In tables by sorted by 'most popular' the listings with the most unique clicks appears at the top of the table, and those with the fewest are at the bottom.
Our comparisons are sorted with top listings appearing at the top of the page when you first visit each table. You can check how each table is sorted, and what criteria we use to determine 'top' by looking above each comparison table. You can refine your results and change how the listings are sorted here too.