The design is such that questions are asked just like a human would structure a line of questioning. The questions asked vary based on what has already been asked and how it was answered.

And Hunch is another search engine with a social aspect. The smarts are a collection of common knowledge derived from users who can submit new topics, questions to ask and decision outcomes.

Hunch says its algorithm is a mathematical framework married with a group of users who provide "personality by contributing to it and making it clever, funny, and nuanced."

Scirus

Scirus is a playground for all things scientific. The site searches more than 485 million science-specific Web pages and is built on technology developed by Fast Search and Transfer, now owned by Microsoft. The Scirus engine focuses only on Web pages containing scientific content. If users search for REM they won't see any results for the popular band.

The search engine picks up peer-reveiwed articles such as PDF and PostScript files and dives into digital archives and patent and journal databases.

Scirus has a range of subject areas including health, life, physical and social sciences. Users can rank results by relevance or by date.

The simple search site also has a link to the latest stories New Scientist News.

The advanced search lets users narrow results based on subject, information (articles, books and so on), file formats and specific sources.

Indeed

Sometimes a search engine can be a uniquely personal experience and so is the case with Indeed, which is a site that aggregates job postings. But you won't submit your resume here or chat on discussion boards; Indeed offers an aggregation of posted jobs on some 1,500 sites from industry sites to corporate job boards.

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Indeed's simple interface lets users type in job keywords and what city they want to work in. The result is a list of jobs in your area.

But that is just where the search begins. Users can narrow the search by salary range, title, company, and distinguish between recruiters looking for applicants and company's searching for employees.

Indeed has a feature that lets users request to look only at the jobs that have been added to the site since they last visited. The site also provides a trending graph for salaries in particular fields and cities, and a month-by-month graph that tracks the number of jobs posted for the category you are searching.