Domain-specific search engines

PubMed is a free search engine accessing primarily the MEDLINE database of references and abstracts on life sciences and biomedical topics.

RecipeBridge is a vertical search engine for recipes,founded by Milwaukee based entrepreneurs Andy Theimer and BillBrennan.

Redlasso is a broadcast media website which allows users to search, clip, and share licensed television and radio content.

Truveo is a search engine for Web video, based in San Francisco and operated by AOL.

GlobalSpec is a technology services company which provides a search engine of engineering and industrial products, indexing over 180 million parts divided into 2,300,000 product families, from over 24,000 manufacturer and distributor catalogs.

Wikiseek was a search engine that indexed Wikipedia pages and pages that were linked to from Wikipedia articles.

Songza was a free music streaming and recommendation service for Internet users in the United States and Canada.

Bizshark is an Internet business search engine and web directory specially designed for competitor analysis, marketing research, business development, and other business processes.

Fiiha is a price comparison service and vertical search engine operates websites in European Union.

Blinkx (London AIM, stylized as blinkx), is an Internet Media platform that connects online video viewers with publishers and distributors, using advertising to monetize those interactions.

Quertle is a biomedical and life science big data analytics company specializing in knowledge discovery and literature searching.

Yummly is a mobile app and website that provides recipe recommendations personalized to the individual's tastes, semantic recipe search, a digital recipe box, shopping list and one-hour grocery delivery.

ZoomInfo is a subscription-based software as a service (SaaS) company based in Waltham, Massachusetts that sells access to its database of information about business people and companies to sales, marketing and recruiting professionals.

The Bioinformatics company PubGene AS is located in Oslo, Norway and is the daughter company of PubGene Inc.

CastTV was a former Internet video search and aggregation company based in San Francisco, California.

Jinni was a search engine and recommendation engine for movies, TV shows and short films.