An email list is a group of constituents you wish to send email communications to. This list can include constituents with specific attributes, like everyone who is attending an event or new members, or it can include all constituents in your database with an email address. 

Email lists are assigned to a List Category. You can think of List Categories as “areas of interest."  List Categories allow you to simplify the subscription process so that subscribers can select which List Category to subscribe to. When the subscriber selects a List Category, they will be subscribed to all email lists that are assigned to that List Category.

Email lists are usually created when you would like to communicate with a group of constituents on a routine basis, send multiple messages to the same group, or use the features of the email marketing templates that include colorful messages with pictures, videos links, hyperlink buttons, and other features.

If you are sending a one time message that does not require pictures, you can use the Direct Email feature. There is no requirement to create an email list for simple messages.