External Authentication - create a short description

I suggest a few little changes

The ExternalAuth module provides a generic service for logging in, registering authenticated users against an external site or service, and storing the authentication details.

(176 character count)

#3 looks good to me, but there's no need for the module name in the short description, so I would tweak to:

Provides a generic service for logging in, registering authenticated users against an external site or service, and storing the authentication details.

I agree about excluding the module name, adding new description to IS.
Moving to RTBC.