Links are a great way of getting noticed, not only do spiders index them, but search engines can look favourably on links, such as links to or from another site. Inbound links are far more worthy too, getting linked from an outside site is an act of trust and knowledge, and from a site in the same field as the website is very agreeable.
Links aren’t the be all end all in SEO, but through links, engines determine popularity of websites and pages based upon other pages and sites popularity and links linking back to your site.
On the otherside though, links can deterioate over time, and this can have an affect on your website. http://www.seoglobalpro.com/seo/links/ http://www.seoglobalpro.com/seo/links/Therefore, not only is it vital to get those links in the first place, but continue to create more links, both from and to your site. This should keep sites and pages both vital and healthy, and keep a main influx of visitors to your site.