Within a page of a website you are able to create meat data. This is data that is only seen by the search engines and is often not shown on the front page of the site for the visitors. Metadata usually consists of a title, description and list of keywords and the idea is to tell the search engine such as Google, what the page is about.
Historically, metadata had a lot of weight in terms of SEO and many marketers used it to get pages ranked for certain phrases. Some SEO experts now believe that metadata has very little or no influence of rankings and therefore often ignore to fill it in.
I believe that it still does have some effect on SEO and therefore should be filled in completely and with the correct keywords that the page is targeting. It is better to complete this information rather than to leave it blank.