Linking is an important part of SEO, but perhaps not in the way that you expect. For a long time, people believed that outbound links to popular sites were better than links to smaller, lesser-known sites. For example, you may consider linking to CNN or Fox News instead of to a local news station. Those other large sites already get a lot of traffic and are very popular and authoritative, so they seem like better options. The thought is that this would increase the search ranking for the page that contained the link.