The Dogpile search engine is different from other search engines in that it does not search the Internet directly, but rather acts as what Dogpile calls a "metasearch" engine for users. Dogpile takes a user search and sends it to all major search engines, then collates the results for users into a single list of results.
The concept behind Dogpile is that all major search engines use different algorithms to try and find the most relevant responses to a user query. Dogpile assumes that major search engines all have their advantages in their individual approaches in how to respond to a user query. In an effort to give users the most accurate and relevant responses possible, it leverages the advantages of each search engine by compiling all of their results for an individual search. It then collates the data together, eliminating duplicate responses to give the user the most comprehensive list of answers possible.
Dogpile hinges its success on user frustration. It's designed for users who are frustrated with responses they receive from normal search engines. Such failed searches often require multiple rephrasing of queries and going to alternate search sites before appropriate responses can be found. Dogpile is designed to automate those steps to provide a more efficient search experience for users. Dogpile's metasearch technology is supposed to weigh responses from the various search engines to display the most truly relevant responses.