Lists, inside the Connections (CRM) Lab, allow you to organize and manage your social connections, contacts, customers, and leads, making it easy to send engagements and communications to specific groups/lists to different target segments (prospects, customers, etc.).
Lists are separated by communication medium: you can create email, phone/SMS, and social connection lists. So, when sharing a piece of content, all you have to do is select the list you want to reach and hit “Send.”
There are also two types of lists available: static and dynamic.
Static lists are relatively fixed lists that you maintain manually, while dynamic lists are generated from how your existing contacts interact with you via various sources (e.g., Twitter Followers, Newsletter Subscribers) and based on the criteria you select.
To learn more about the difference between the dynamic and static list types, check out What are Dynamic Lists?