Dogpile is a metasearch engine for information on the World Wide Web that fetches results from Google, Yahoo!, Yandex, Bing, and other popular search engines, including those from audio and video content providers such as Yahoo!.
Dogpile began operation in November 1996. The site was created and developed by Aaron Flin, who was frustrated with the varying results of existing indexes and intending on making Dogpile query multiple indexes for the best search results. It originally provided web searches from Yahoo! (directory), Lycos (inc. A2Z directory), Excite (inc. Excite Guide directory), WebCrawler, Infoseek, AltaVista, HotBot, WhatUseek (directory), and World Wide Web Worm. It naturally drew comparisons with MetaCrawler, a multi-threaded search engine that had existed before, but Dogpile was more advanced, and it could also search Usenet (from sources including DejaNews) and FTP (via Filez and other indexes).
In August 1999, Dogpile was acquired by Go2net, who were already operating MetaCrawler. Go2net was then acquired by InfoSpace in July 2000 for $4 billion. Dogpile received a design facelift for the first time in December 2000.
In November 2008, Dogpile launched its "Search and Rescue" program, which donates money to animal-related charities, "helping US soldiers bring home rescued dogs from Afghanistan"  The program also helps people find help for animals in need. By early-December 2008, people using the Dogpile search engine had raised $100,000 for Dogpile's Search and Rescue program.
OpenMail was later renamed System1, which also operates another search engine at:
In April 2005, Dogpile (then owned and operated by InfoSpace, Inc.) collaborated with researchers from University of Pittsburgh and Pennsylvania State University to measure the overlap and ranking differences of leading Web search engines in order to gauge the benefits of using a metasearch engine to search the web. Results found that from 10,316 random user-defined queries from Google, Yahoo!, and Ask Jeeves only 3.2 percent of first page search results were the same across those search engines for a given query. Another study later that year using 12,570 random user-defined queries from Google, Yahoo!, MSN Search, and Ask Jeeves found that only 1.1 percent of first page search results were the same across those search engines for a given query.
These studies showed that each search engine provides vastly different results. While users of the search engine may not recognize a problem, it was shown that they use ~3 search engines per month. Dogpile realized that searchers are not necessarily finding results they were looking for in one search engine and thus decided to redefine their existing metasearch engine to provide the best results.
- Category Links: Links to help users focus their search on specific categories like News, Audio, etc.
- Yellow Pages: Allows users to do a search using the Yellow Pages.
- White Pages: Allows users to do a search using the White Pages. (No longer available as of Feb 23, 2017)
- Web Search Box: The area where users enter the search term. Enter keyword(s) and hit the Search button to retrieve the results.
- Search Button: The button pressed to search for results.
- Preferences: Links to a page where users can set a variety of customized search preferences.
- Spelling Correction: Offers suggested spellings for words that may be misspelled and automatically corrects commonly misspelled keywords.
- Search Filter: Blocks potentially explicit content for multimedia searches in Moderate setting and for all searches when in Heavy setting.
- Statistics Bar: Shows how many results were returned for the search term.
- About Results: Find out about Dogpile's policies regarding sponsored and non-sponsored search results.
- IntelliFind: Recommends additional content based on the original search term.
- Are You Looking For?: Offers suggested spellings for words that may be misspelled and other search keywords that seem to be related to the original search term.
- Recent Searches: Keeps track of the 15 most recent searches. The list resets when the browser is closed.
- Favorite Fetches: Shows recent popular searches from other users
- Internet Resources for Engineers, by Jimin He