site/_includes/related_pages.html

<hr />

<!-- code doesn't work -- tags work much better, but leaving this here in case i figure out the issue. -->

<h3>Related Pages</h3>

<ul id="related_pages">

{% assign currentTitle = page.title %}
{% for tag in page.tags %}
{% assign counter = '0' %}
     {% for page in site.pages %}
        {% if page.tags contains tag and page.title != currentTitle and counter < '10' %}
        {% capture counter %}{{ counter | plus:'1' }}{% endcapture %}
        {% assign pageList = "" | split: "|" %}
        {{ pageList | push: page.title }}
        {% endif %}
      {% endfor %}
     {% assign unique_pageList = pageList | uniq %}
     {% for item in unique_pageList %}
         <li><a href="{{ item.url}}">{{item.title}}</a></li>
     {% endfor %}
  {% if counter == '0' %}<span class="noOtherPages"><p>No other pages.</p></span>
  {% endif %}
{% endfor %}

</ul>