The original proposition of a web search engine was to help you find the answer to your information need in a page or site on the web: if someone has already solved your problem, let us help you find their solution.
There are still many search scenarios where this is the expectation of the users. One that comes (frequently) to mind is finding solutions to coding issues or API usage on coding forums and question answering sites like StackOverflow.com.
However, there is a relatively new class of queries for which search engines like Bing and Google provide satisfaction immediately. For example, a query like 'who wrote To Kill a Mocking Bird' produces the following results:
There are many other examples of this type of direct question answering.
The question is - how will user expectations change and how will it impact the long tail of sites on the web. For example, the following query does not yet produce a direct answer in any search engine 'How much is 1 pound from 1811 worth in current money?' (a question a daughter might ask a father when watching a period drama on the beeb). A search engine can, however, and will provide a link to a site which can answer the question (e.g. Measuring Worth).
I would argue that this is directly where we are headed.
Related post: Did Web Search Kill Artificial Intelligence?