What is 'Related lists' based on?

When you view a movie list, there's a gray box at right called 'Related lists.' What's the criteria used to determine that lists are related? I just clicked on the top 'Related list' and it didn't have a single movie in common with the one I was viewing, nor was it voted for by a single user who voted for the current list. And it was created by a user I hadn't even seen before. Does it get down to movies that have the same actors/directors/writers? Or movies that have the same words in the tags or description?

If so, those are pretty weak associations and it would be nice to have some indication of that. Maybe there could be a "This list was recommended based on your interest in:" and then give the list name or movie title/actor/tag/description words like Netflix and Youtube do for their recommendations.

It is purely based on the title of the list you are viewing and description and titles in the related lists. This could probably get a lot better with tags on lists, I am redoing the view list page soon so I will hopefully be able to improve it.

The purpose of the current box isn't to show recommended lists, it is supposed to show lists that are related to the theme of the list your are viewing.

I have considered using votes 'people who voted for this list also voted for' to show a recommended lists box or combine them in some way, I think it would produce interesting results but not necessarily lists related to the list you are viewing.

Youtube do for their recommendations.

I've noticed with their new design youtube doesn't seem to use any kind of wording but I believe the right hand list of videos is mostly based on the title and tags for the videos.

It is purely based on the title of the list you are viewing and description and titles in the related lists.

Ok, good to know; I'll put more thought into what words I use in my list titles and descriptions, then, based on observing what other people use.

I've noticed with their new design youtube doesn't seem to use any kind of wording but I believe the right hand list of videos is mostly based on the title and tags for the videos.

Yes, I was thinking of the 'Recommended for You' section on the front page where they use the 'Because you watched:' wording. The right-hand list may also be based on things like what people search for soon after they search for something and don't find what they're looking for (indicated by not clicking on any of the results or watching only part of a video) because I've done searches for English translations of foreign movie titles and still get results (in the main list and the right-hand box) that only have foreign-language-character titles and tags. Although they may just be translating the words automatically with a translation program.

The purpose of the current box isn't to show recommended lists, it is supposed to show lists that are related to the theme of the list your are viewing.

But it seems like the strongest indicator another list is related to the current one would be that it contains some of the same movies or at least some movies that I've either rated/watched/want to watch. If it doesn't contain any of those, even if its closely related, I'm unlikely to use it for recommendations unless I go to the profile of the user who made it and find we have similar ratings on other Items. I appreciate that there are still non-recommendation uses for such lists like "Best actors for Theme X." Maybe such a list would turn up as a Related List for one of your movie lists of all the movies of a given actor and you happen to also have an interest in Theme X.

But with descriptions there's more room for ambiguity. If I make a list of the most boring movies I've ever seen and say in the description "Clipping your toenails is more entertaining than watching these movies." will I get Related Lists like "Sockless scenes that are anything but boring," "Sexiest feet to walk the earth," "Pedicured to perfection," "Toes to die for," etc.? This will seem quite mysterious and erroneous and make users distrust the system: both whether the program running it has bugs and whether the relationships it points out are useful often enough that its worth bothering with. Unless there's some explanatory wording of the rationale between the relationships--then users may say "Oh, so that's why" and be confident that the system at least makes some sense, even if the relationships seem totally out of left field a lot of the time. (Even better would be if there were some way of training the system like voting thumbs up or down for the relationship.). But with tags, actors, writers, directors, etc. factored into the equation, maybe there will be less of this kind of thing.

I have considered using votes 'people who voted for this list also voted for' to show a recommended lists box or combine them in some way, I think it would produce interesting results but not necessarily lists related to the list you are viewing.

Right, but with a title like 'People who voted for this list also voted for,' you'd know what to expect. It could still be factored in to the related lists determination as well--it would just need to have a very low rank (how much weight it carried in making the final decision).

But it seems like the strongest indicator another list is related to the current one would be that it contains some of the same movies or at least some movies that I've either rated/watched/want to watch.

I think title/keywords are the strongest indicators, lists with similar movies could be used but I can think of some cases where lists do not share the same items but are related in theme e.g. "Top 10 werewolf horror movies" and "Top 10 zombie horror movies" are related in theme but probably wouldn't share any movies. Also I think there are times where items (especially for actor lists) there they could be in both lists but the theme is completely different.

Having said this I will still experiment what results come up comparing items in different lists.

But with descriptions there's more room for ambiguity. If I make a list of the most boring movies I've ever seen and say in the description "Clipping your toenails is more entertaining than watching these movies." will I get Related Lists like "Sockless scenes that are anything but boring,"

No because it only uses the title of the list you are viewing and then compares against the title and description of other lists. I tried using both title and description but the results were worse as you have pointed out here.