WSO2 Identity Server (IS) allows for authentication using various authenticators including social network identities, multi-factor authentication, and federated identities. It supports single sign-on, federated identity, user provisioning and management. The document discusses authenticators in WSO2 IS like OAuth2/OpenID Connect, SAML SSO, and multi-factor authenticators. It also covers features like configurable authentication flows, just-in-time user provisioning and management capabilities in WSO2 IS.