Basecamp is an online project management tool that allows users to create projects, discuss tasks, exchange messages and files, track progress, and keep teams organized in one central place. Key features include campfires for group discussions, a message board for private messaging, to-dos for outlining tasks and assigning people, a schedule to track milestones and deadlines, automatic check-ins to regularly check on the team's status, and a documents and files section to store and share project materials. The tutorial demonstrates how to sign up, set up a project, and use these features to collaborate effectively with teams.