Orphaned pages, since they have no links to them from other pages, are difficult to find, and are most likely to be found only by searching, or by chance. Because of this, few people know they exist, and therefore, they receive less readership and improvement from those who would be able to improve them. It is therefore preferable that they can also be reachable by links from related pages. You can help by adding links from other suitable pages with similar or related information.
A page, however, may have links to it from project and talk pages, but not from any other mainspace articles. These, along with generally underlinked articles, are listed in Category:Orphaned articles.