Just a few thoughts…
Organic/Natural or White Hat Search Engine Optimization is the proven method to build backlinks naturally with link-backs to your site creating a gradual increase over time. Failure to continually manage these natural/organic backlinks would cause the reverse effect – a gradual decrease over time with the over all result of no traffic.
On page SEO or Search Engine Optimization uses title tags and description optimization. It also includes internal linking structures helping your link juice flow from one page to another in an organized method. This internal linking helps your visitors find what they’re looking for.
On Page SEO also helps your page ranking as Google Panda updates are narrowing down “real backlinks” and “spam backlinks” ranking your site as “high quality” or not.
Off Page SEO or Search Engine Optimization involves sites linking back to you with the right anchor text. You want sites like yours to link to you. Backlinking strategies can be tricky and require a lot of time and energy. Too many backlinks (density too high) and your site will look artificial causing your rankings to drop.