While all search engines use one form of caching or another to build their indices, some of them make a point of displaying cached web pages to their users. The commonly quoted pretext for this is that it offers searchers fast access to a page’s content, making it easier to check out whether it’s what they are really looking for in the first place. Of course, what this actually does is keep visitors on the search engine’s site, making them more susceptible to banner ads and other means of promotion.