Google+ and Wave were both doomed because they were invite-only. If you have to ration invites, it isn't much of a social network. Invite-only successfully crea

Google+ and Wave were both doomed because they were invite-only. If you have to ration invites, it isn't much of a social network. Invite-only successfully created artificial demand for Gmail because invited users could immediately communicate with non-Gmail users. That didn't work for Google+ or Wave since they didn't interoperate with services that people already used.