Answers to some questions in life cannot be captured within a Google search box. Sometimes, we have questions like “Are apartment rents increasing in New York City when a lease is renewed?” or “What is the best cat food brand out there?”—things we would choose to ask a real person rather than a search engine only if we knew who to go to. To address this market gap, several prominent sites have emerged to provide a link between human questions and human answers. “Social search”, as it has come to be called, utilizes human knowledge that even Google cannot tap into.
Social search is still in its infancy compared to algorithmic-based search engines, currently accounting for 4 percent of the total market. Nevertheless, it seems that some of the big companies see opportunities in the field, as reflected by Google’s acquisition of Aardvark 
(a Q&A site started by an ex-Googler), Benchmark Capital’s investment in Quora 
(founded by ex-Facebook employees), and Facebook’s introduction of the new Facebook Questions 
feature, all of which took place this year. Social search, which tends to be more personal and expressive, gives new and deeper insight into user data. Thus, it could potentially be a lucrative location for more targeted advertising, although the profit mechanism for these sites is yet to be realized.
Here are some of the major social search sites and their features:
- Users can submit questions directly to Aardvark’s search site Vark.com via web, IM, email, Twitter, or iPhone
- Aardvark searches through all of the people in the user’s network who are available over IM or email to find the right match
- If access to Facebook is given, it will gather information from the user and his/her friends’ profiles—geographic or work networks, interests, etc.
- The social data will be used to select individuals to send the questions to for answers
- Online question-and-answer community
- Any registered users can provide answers to the questions; moderators oversee the activities
- “Federated Flutter ” (launched August 2010) allows third parties to integrate Q&A on their websites and increase traffic through organic search
- Anyone can add questions and answers
- Users can follow questions, topics and people, creating a stream of relevant questions and answers for each user
- As of August 6th, search engines like Google can index  content on Quora
- Users can call or text questions from their mobile phones to ChaCha, and the question is routed to the most knowledgeable person on the topic in the Guide community
- The questions and the answers written by the Guides are available on the ChaCha website
- The answers are provided by ChaCha Guides, independent contractors working for ChaCha
- “A human-powered search engine and a knowledge sharing service”
- Registered Mahalo users share their expertise
- Users can tip each other for their information in Mahalo Dollars , which can be cashed-out or spent at the Mahalo Store
As mentioned earlier, the user data along with the Q&A threads can reveal dynamic information about the participants. Conversations sometimes contain information on user demographics, age, and gender, all of which can be used as the basis of targeted advertising. There is no doubt that the social search market is gaining more and more exposure, and the audience base of social search sites is growing. Companies are interested about the investment opportunities in the social search market, and hopefully it will come about as a profitable innovation, just like how Google and Twitter did.
What do you see as the potential for these "human-powered" search engines. Can they become profitable on their own? Or will Google and Bing incorporate the functionality and render them obsolete?