From the About Us page:
SearchWorkings.org was created by a bunch of really passionate search technology professionals who realised that the world (read: other search professionals) doesn’t have a single point of contact or comprehensive resource where they can learn and talk about all the exciting new developments in the wonderful world of open source search solutions. These professionals all work at JTeam, a leading supplier of high-quality custom-built applications and end-to-end solutions provider, and moreover a market leader when it comes to search solutions.
A wide variety of materials, from whitepapers and articles, forums (Lucene, Solr, ElasticSearch, Mahout), training videos, news, and blogs.
You do have to register/join (free) to get access to the good stuff.