The old mantra "The more links the better" doesn't hold as much water as it used to. It may have worked earlier, when the Internet was more manageable. In keeping with an ever growing Internet and increasing misuse of link exchanges, search engines have now adopted different, varying criteria for ranking web sites.
Today, an over abundance of links from irrelevant, low-ranking sites and link farms could actually cause you more harm than good - getting your site penalized. While links continue to be vital to the success of your website, what is important for SEO purposes is that you use a wide variety of anchor text and seek out one way links only with sites that are relevant to yours.