Nice overview of Chacha at Read/Write Web, a real Human Intelligence powered search engine that help you find what you are searching for.
Written by Alex Iskold and edited by Richard MacManus
In this article we look at ChaCha, a search engine which brings a fundamentally different kind of intelligence to the problem - human brain power.
The current implementation of ChaCha offers a combination of automation and people-powered search. The results can be organized by a vertical, like images or news. Also it has a set of related searches. But by far the most interesting and unusual aspect of ChaCha is its people-powered search.
ChaCha employs people to help users sift through the results. This is cleverly done using a familiar chat interface. When you first come to the site, you are presented with a standard search box. Type in a query and you get back a traditional list of matches. In the testing we did, we found both the performance and quality of the results to be quite good.