This document discusses Aardvark, a large-scale social search engine. It begins with an abstract that introduces social search engines and notes how Aardvark differs from traditional hypertextual search engines by using a user's social network as an information source rather than documents. The document then covers Aardvark's architecture, how it works by socially crawling profiles, indexing people, analyzing questions, ranking results, and its user interface. Examples are provided to illustrate how Aardvark routes questions to experts in a user's network to provide answers, unlike traditional search engines that return documents.