IKO - Initial keyword offering - pre-sale of Keywords for life.
Apache Lucene - High-performance, full-featured text search engine library written entirely in Java.
Geckoboard - Get to know Geckoboard: Instant access to your most important metrics displayed on a real-time dashboard.
Six Degrees of Wikipedia - Find the shortest path between two subjects
WikiPearl - Plastic-Free Food Packaging
Sphinx Search - Sphinx is an open source full text search server, designed with performance, relevance (search quality), and integration simplicity in mind. Sphinx lets you either batch index and search data stored in files, an SQL database, NoSQL storage.