I recently earned a link from one of Wikipedia's websites. One of the site's authors referenced one of the niche sites that I work on as a test site. With this site, I focused on building valuable content for people that are interested in becoming high jumping athletes. The site is less than 5 months old at the time of recording this video. Good content earns links, but it is a combination of timing and opportunity.
Almost everyone that has been involved in SEO before Penguin hit has had some experience with using PR newswires or PR syndication sites. These were used to blast res releases in the hope that the press release would get picked up and published by other websites and journalists.