By default all the lists you created are private lists and can be found in "My lists" in the Media list page.
When you create a new list, there's an option to allow you to make the list public. You can also make a list public after it's created. By making a list public, the list will be accessible from the all public lists category by the public. The data made public will include all contact details (people will still need to have a supported plan to access contact details) and notes. However, your pitches sent to a public list will never be made public.
Only the list owner can edit a public list.
People can subscribe to a public media list for easier access. Subscribed media lists can be found in Subscribed lists. A subscribed list updates automatically once the list owner updates it.