I've installed the haystack app and I'm using the solr backend. Search works perfectly although when I try to use the more_like_this template tag, nothing is returned.
I have added <requestHandler name="/mlt" class="solr.MoreLikeThisHandler" />
to solrconfig.xml and I can make queries at http://127.0.0.1:8080/solr/mlt
The template is fairly basic
{% load more_like_this %}
{% more_like_this video as related_videos limit 5 %}
{{ related_videos }}