What are the best vertical search engines?

1. SkyScanner.net – The leading flights search engine, providing information about all carriers to help you find the best deal. 2. Momondo.com – Very similar to SkyScanner and with an added 'current searches' widget to see what flights other people are searching for.

Hi Friend,
It searches over 200 travel sites to give me the best deals on airfare, hotel, cars, and vacations. Only a few years old, Kayak is the clear leader in this vertical. It even bought out its main rival sidestep.com for $200 million a few weeks ago.

A vertical search engine is distinct from a general web search engine, in that it focuses on a specific segment of online content. ... Some vertical search sites focus on individual verticals, while other sites include multiple vertical searches within one search engine.

Examples of vertical search engines include the Library of Congress, Mocavo, Nuroa, Trulia and Yelp.