&gt; Except for HN, Twitter &amp; Reddit, are there any services that don&#x27;t use email for login?<p>I guess sites that use the username as a form of identity within a site. Email address usernames are just identifiers and contact information, without really being linked to an identity.<p>I would think if auth was being written from scratch it&#x27;d probably default to email based usernames. That ship has sailed though.