Collaboration with Email

For most the last 25 years or so, most people with “office” jobs have relied on email as their primary communications tool at work. During that time, Microsoft has added many ways for groups of people to collaborate within their email clients. Distribution lists, public folders, shared mailboxes, resource mailboxes, site mailboxes, and now Groups each give end-users different functionality. How does an organization decide which of these options to use? When are shared mailboxes the best choice?