You may have heard that search-engine gorilla Google is in the midst of an infrastructure change. As a company that generates revenue by serving advertising alongside its search results, Google has an interest in serving up relevant search results in a timely manner.
If it doesn't, then someone else will do a better job and searchers will go somewhere else. Then no one will see the advertising or click on it, resulting in less revenue for Google. It's a nice straightforward model.