This document discusses advanced search and indexing capabilities in Liferay 6.1, including integrating external content sources. It describes using Solr 4 for its improved features, SolrCloud for high scalability, and ManifoldCF for crawling external repositories. The solution presented indexes both internal and external content in a unified Solr index, and displays external search results alongside internal results using custom plugins and faceted search configuration in Liferay.