All calls to the Yahoo Social APIs require authorization with the OAuth protocol For instructions and requirements, see the Yahoo OAuth Quick Start Guide.
To safeguard user data and authenticate API calls, you are also required to use SSL (HTTPS) to access to the Social Directory APIs, whether you're using the REST API or the YQL tables.
In addition to authentication, most Yahoo user data is protected by scopes. A scope is a permission setting that specifies access to a Yahoo user's non-public data. For more information, see Scopes (Permissions).