The feature appears alongside the visibility options on the the list edit page. Both options have been moved to the top of the page and now show who can see and edit the list.
The feature is easy enough to use but it does come with a downside that contributors have the same administration rights as you do in maintaining the list. For that reason you'll need to make sure that you only make content public that you are willing to have changed. Also, a warning that once you open your list, there is no turning back.
When you open a list, your avatar will appear in a contributors box, ranked by the number of contributions. Anybody seeing the list for the first time will see the same edit listbuilder and sort list icons.
A lot of the discussion that centres around lists, has to do with changes or alternative translations so it makes sense to open them up so changes can be made by everyone.
There are a few small interface issues that need to be worked out, including how you can see which of your own lists are open. Something else I'd like to see is a way of finding lists that are open so I can contribute to them.
It sounds as though there are lots of good things to come from the smart.fm team in their effort to make things more social. To get into the spirit of things I am opening up three of my most popular lists so you can contribute to them, go crazy!
Expressive Japanese Adverbs
Adverbs you can use to express yourself colourfully in Japanese. Originally for my students in Fast Track to Fluency in Japanese on eduFire, now it's yours to add your own flair!
Essential Japanese Groceries
Food and other things you might need to buy to survive a few weeks in Japan. Made originally for students of Japanese for Beginners on eduFire. If you want to expand on this list, feel free!
Useful Everyday Japanese Expressions
Habit forming phrases for everyday use. Originally intended for my class, Japanese for Absolute Beginners on eduFire. Now an open list so you can make it more useful than ever!
If you're using these lists already, I want to see your avatar in the contributors box, especially if you've commented about changes that need to be made. If you're not using smart.fm, get on it right away!