SEO: robots.txt with sitemap, related posts links, canonical tags, better CTR snippet

site/layouts/_default/baseof.html

@@ -5,6 +5,11 @@
   <meta name="viewport" content="width=device-width, initial-scale=1.0">
   <title>{{ block "title" . }}{{ with .Title }}{{ . }} | {{ end }}{{ .Site.Title }}{{ end }}</title>
   <meta name="description" content="{{ with .Description }}{{ . }}{{ else }}{{ .Site.Params.subtitle }}{{ end }}">
+  <link rel="canonical" href="{{ .Permalink }}">
+  <meta property="og:title" content="{{ with .Title }}{{ . }} | {{ end }}{{ .Site.Title }}">
+  <meta property="og:description" content="{{ with .Description }}{{ . }}{{ else }}{{ .Site.Params.subtitle }}{{ end }}">
+  <meta property="og:type" content="{{ if .IsPage }}article{{ else }}website{{ end }}">
+  <meta property="og:url" content="{{ .Permalink }}">
   {{ partial "adsense/head.html" . }}
   <link rel="stylesheet" href="{{ "css/main.css" | relURL }}">
 </head>

site/layouts/_default/single.html

@@ -9,5 +9,6 @@
     {{ .Content }}
   </div>
   <p class="muted back-link"><a href="{{ .CurrentSection.RelPermalink }}">← Back to {{ .CurrentSection.Title }}</a></p>
+  {{ partial "related-posts.html" . }}
 </article>
 {{ end }}

site/layouts/partials/related-posts.html

@@ -0,0 +1,12 @@
+{{- $related := first 4 (where (where .Site.RegularPages "Section" "posts") "Permalink" "ne" .Permalink) -}}
+{{- if $related -}}
+<aside class="related-posts">
+  <h3>Related articles</h3>
+  <ul>
+    {{- range $related }}
+    <li><a href="{{ .RelPermalink }}">{{ .Title }}</a></li>
+    {{- end }}
+  </ul>
+  <p class="related-cta">Try the examples in <a href="https://xsltplayground.com">XSLT Playground</a> — free online XSLT editor and tester.</p>
+</aside>
+{{- end -}}

site/layouts/robots.txt

@@ -0,0 +1,4 @@
+User-agent: *
+Disallow:
+
+Sitemap: {{ .Site.BaseURL }}sitemap.xml