Using Appcues + Segment with anonymous visitors. This snippet can safely be added to your site via Google Tag Manager.

snippet.html

<script>
  (function() {
    if (analytics != null && analytics.ready != null) {
      analytics.ready(function() {
        if (window.Appcues != null) {
          if (analytics.user().id()) {
            // Identify known user.
            Appcues.identify(analytics.user().id(), analytics.user().traits());
          } else {
            // Identify as an anonymous user.
            Appcues.identify(analytics.user().anonymousId())
          }
        }
      })
    }
  })()
</script>