Your entire supporter database is housed in your control panel. There are many ways NationBuilder lets you view, catalogue, and manage all of this information beginning with a master list of everyone in your database. There are multiple drop downs that allow you to pull that list by different search criteria; there is even a drop down exclusively for filters that you have created using the advanced search function. Advanced search, allows you to comb through your database in great detail, giving you access to dozens of different search criteria.
NationBuilder also lets you create tags and saved lists of people. Tags give you the ability to mark people as they take action on various pages of your site. Tag everyone who has attended a specific event, or has specified an interest in a certain topic. The plus button next to a person's name allows you to select the person and put her on a saved or new list.