You can sign in to Quick Timesheets using Google Apps, Gmail, Atlassian Crowd or your own OpenID provider.
To enable the feature, visit the Authentication page in your Quick Timesheets Settings, and choose a single sign-on (SSO) service for your users to authenticate with.
SSO allows you to authenticate against a central authentication authority, such as LDAP or Microsoft Active Directory (AD). This could for example allow your users to login to Quick Timesheets using their AD credentials.
Quick Timesheets will authenticate the SSO sign-in with the email address of their Quick Timesheets account. As a fallback users will always be able to login using their username and password.