Official Google Blog: Encouraging people to contribute knowledge
Why Google is the most popular search engine, the reason is that it enables you to access the information contained web which has enormous amount of information with its advanced search technology.
millions of people have knowledge which they want to spread, also with billions of people who wish to acquire the knowledge, but the challenge is how to make them share their knowledge.
a whole lot of information with most are not well organised and not well written but of great importance, to make it easily discoverable
Google is on its way to do so .