You undoubtedly have seen the “Made Fresh Daily” sticker or signage at the grocery store. If you buy the product you expect it to be dated and set to expire today. This gives you a sense that the product is as fresh as possible. In many upscale restaurants, chefs will go to the docks and market to purchase fresh supplies for their kitchens. They want their customers to recognize that they offer the finest ingredients in their recipes. We can learn from this approach of fresh food in search engine ranking.
Search engines love fresh content and so do people. Like fresh food, content can be fresh and relevant and in some cases that information expires daily (i.e. news). People looking for good information related to their needs and turn to search engines. Google and other search engines try to figure out what results best match the intent of the search to return the most relevant information. Search engines then need to figure out when a website has new content. The more you update the content the more often search engines will visit and index your site. Twitter for example, content is updated by the second and as such it is indexed and listed by the second. The more content you offer the more search engines will index your site. Just make sure it is good, fresh, and relevant information.