Google announced more than 10 new features for Google Search Appliance (GSA), including one that automatically improves results over time, the “Self-Learning Scorer” –  analyzes employee clicks and behavior to automatically fine-tune and improve its built-in relevance. For instance, if most users click on the fourth result for a given query, the GSA recognizes that and automatically boosts its placement – without any intervention from an administrator. Along with our existing and intuitive biasing features and Ranking Framework, this provides ease of relevance tuning.

GSA 6 -- New Features:

GSA 6 - Self Learning Scorer:

Full Article: Enterprise blog