The reason backlinks are in the front of peoples' minds is that they are the basis of Google's Pagerank Technology. The makers of Google reasoned that the more popular a site, the more links would point to it. This was the foundation of Google's revolutionary search engine.
However, backlinks can be manipulated (search engine abuse) and the quality of Google's search results suffered as a result.
Therefore, Google began tweaking its algorithm to include other signals to determine how a page should rank in its index. Backlinks are no longer the end all and be all of getting traffic and rankings and in fact, too many unnatural looking links and your site can sink like a rock.
Today's secret to rankings is no secret. Build high quality content that pleases human visitors. Make it especially useful and unique and you have a much better chance of ranking AND surviving future algorithm shifts.