It depends what you mean by email. For example, FWD:Everyone (fwdeveryone.com) allows using the Gmail add-on as the only interface between the user and service. So the user can stay entirely within their inbox, but they aren't interacting with the service by sending or forwarding an email.
Thanks. By email I mean send to an email address, and something happens. FWD:Everyone is more a add-on to a tool (that happens to send/receive emails) than an email-as-interface service.
Comments
It depends what you mean by email. For example, FWD:Everyone (fwdeveryone.com) allows using the Gmail add-on as the only interface between the user and service. So the user can stay entirely within their inbox, but they aren't interacting with the service by sending or forwarding an email.
Thanks. By email I mean send to an email address, and something happens. FWD:Everyone is more a add-on to a tool (that happens to send/receive emails) than an email-as-interface service.