Lists don't work and Groups are not a response to Google+ Cirlces.
Lists (in Facebook) suck - they UI is hidden and terrible.
Facebook Groups came out when the author expected Facebook to respond to the concepts behind Google+ Circles. It turned out that it wasn't a response to those concepts at all, and was something unrelated.
(BTW, it's not me down voting you.)
(me) nlothian @dhanji Can you settle an argument on HN? Do you know about Facebook Lists or not? http://news.ycombinator.com/item?id=2749711
@nlothian Yes, of course I do. Someone on there has already answered it: news.ycombinator.com/item?id=2749651