When you’re creating a snap, you can freely mix different types of content in modules. One type of module is referred to as a ‘list,’ and it’s what you see referred to as ‘social lists.’ List modules are flexible enough that, if you want, they can take contributions from readers much the way snaps accept related links, and if you want, those can be voted up or down in the list. Here is a social list snap from a while back. It’s a bit like snaps are voted up or down. Like related links, there is a limit to the number that you can contribute to any one social list, which grows as you level up. Not often seen, there had been some bugs with these not that long ago, as I recall. Heaps of promise, though.