Single Sign-On (SSO) allows users to authenticate once and gain access to multiple services without needing to log in repeatedly. This increases productivity and user satisfaction by streamlining access to authorized resources. LDAP, while used for managing user information, is not specifically a single login solution. Kerberos is a network authentication protocol designed to provide strong authentication for client/server applications but does not, by itself, provide the full SSO user experience. A password manager assists in creating and storing strong passwords but does not enable unified access to multiple services with a single authentication event like SSO does.