More like this with Search API and SOLR

Here is a recipe for creating a More Like This block using search_api_solr. Note: both apachesolr and search_api_solr leverage Solr's builtin more like this feature. It is, therefore, not available to normal search.

  1. Enable some modules: search_api, search_api_solr, search_api_views
  2. Create a Search server of the Solr class.
  3. Create a Search index (or use the Default node index) and point your Solr search engine at it.

  4. Create a new view on your search index NOT on Search index. eg:

    Show *Default node index* sorted by *unsorted*

  5. Continue and edit.

  6. Reveal Advanced and Add a Contextual filter.
  7. Filter on Search or scroll down to find Search: More like this.
  8. Configure by selecting the Fields for Similarity that you want to determine likeness on.

http://drupal.org/node/1250304#comment-4870278