When working with recommendations SharePoint 2013 Search records analytics events. Unfortunately those events are not being recorded for anonymous users.
On public-facing websites enable the Usage Cookie to track anonymous visitors.
In search queries use the XRANK function to boost content where a particular Managed Property matches the search query.
On public-facing websites using cross-site publishing use the Catalog Item Rank Model rather than the Default Search Model to get more relevant search results.
When resetting List’s permissions anonymous access to the catalog is removed as well.