I found a Reddit thread explaining the different comment sorting systems. Does LW use the same algorithms for each method?

http://www.reddit.com/r/TheoryOfReddit/comments/1y8rst/what_is_the_best_way_to_sort_top_best_new/

Missing from their list though are "popular" and "leading" (and "old", but that's pretty self-explanatory). I'm guessing "popular" is the same thing as "hot", judging based on what appears in my address bar when I sort that way. "Leading" is listed as "interestingness" in the address bar, which leads me to think it adds weight to comments that inspire a lot of discussion. My observations suggest that it also factors in votes though. Could someone please clarify further on what these algorithms do?