Category filter returning all entries I've been trying to build a category filter. I managed to make my buttons respond with categories but the returned entries on the page stay the same. So when I click one of the links "/?category=koop" gets added to the URL, but my entries don't respond upon that URL. I do have added the categories in the CP and assigned them to my entries. 

Here is the code of my filters:

{% if craft.request.getParam('offerCategory') is not null %}

    {% set offerCategory = craft.categories.slug(craft.request.getParam('offerCategory')) %}
    {% set offers = craft.entries.section('offers').relatedTo(offerCategory).find() %}

{% else %}

    {% set offers = craft.entries.section('offers').find() %}

{% endif %}


And my button list

{% for offerCategory in craft.categories.group('offerTypes').find() %}
    &lt;li&gt;
        &lt;a class="mart-button" href="{{craft.request.url}}/?category={{ offerCategory.slug }}"&gt;{{ offerCategory.title }}&lt;/a&gt;
    &lt;/li&gt;
{% endfor %}


I'm quite new to Craft. One of the resources I'm using to build this is: http://craftcookbook.net/recipes/197. 

If anyone knows what I'm overseeing, thanks in advance.
I suggest changing the couple places where you use getParam('offerCategory') to getParam('category') so it matches the parameter set in the URL.