four11.com, an early (1995?) opt-in contact directory. Vaguely recall it supporting LDAP. When Yahoo bought it in 1997 they promptly shut off everything but th

four11.com, an early (1995?) opt-in contact directory. Vaguely recall it supporting LDAP. When Yahoo bought it in 1997 they promptly shut off everything but the web mail, much like Comcast buying Plaxo a decade later and killing most of the utility of Plaxo once the deal closed.