I’ve not been into Facebook for some time, and so have only just found the Friends list; which I know has been discussed for some time.
It’s easy to add people to, potentially easier than Elgg; and, like Elgg, the same person can be in more than one list. I’m not quite sure what a list does, other than the fact you can message a list, rather than selecting friends individually; and you can invite lists to particular events. I’m not sure if other things – such as news items – can be filtered just to particular lists.