Trying to list entries related to users with a specific category selected
I think I worked this out. It looks like the related entries need to be contained in the user loop. This is what I used to make this work:

{% set categoryUsers = craft.users.relatedTo(category) %}
    {% paginate categoryUsers.limit(1) as entries %}

        {% for categoryUser in entries %}
            {{ categoryUser.username }}

            {% set categoryEntry = craft.entries.section('jobs').authorId(categoryUser.id).first() %}       
                {% if categoryEntry %}
                    {{ categoryEntry.positionTitle }} (And other fields not added yet.)
                {% endif %}

             &lt;p&gt;Testing the total found: {{ categoryUsers|length }}&lt;/p&gt;
        {% endfor %}

    {% if paginate.prevUrl %}&lt;a href="{{ paginate.prevUrl }}" class="pagination left"&gt;&amp;laquo; Previous Page&lt;/a&gt;{% endif %}
    {% if paginate.nextUrl %}&lt;a href="{{ paginate.nextUrl }}" class="pagination right"&gt;Next Page &amp;raquo;&lt;/a&gt;{% endif %}

    {% endpaginate %}


Still testing, but I think this is the solution. (Unless someone else has a better way of doing this. :))