SEO is the collective term pertaining to the techniques used to help your net site appear in the search results when people type key words that are relevant to your niche or business. There is lots of techniques used in SEO but perhaps the most important is building backlinks.
What are SEO Backlinks?
There are fundamentally types of links. Outbound links are the links you made on your site, pointing to other web pages outside your net site. Backlinks are the links coming from other sites pointing to pages on your net site.
So why are backlinks vital to search engine optimization? Well, the more backlinks you have, the more popular your net site is. And when you have a popular net site, Google will think of your site as an "authority." When your net site is deemed an authority, it will rank high on the search results pages.
Backlinks also serve as a kind of recommendation and search engines like Google think about this important. You see, search engines like Google is in the business of giving users the net pages that they need, and when other sites are recommending yours (by linking to your site) then in the eyes of Google, your net site must be what the users are looking for.
Google also monitors how much traffic your net site gets, and when you have lots of backlinks, it means increasingly people will go to your net site. Since you are getting more traffic, it is more likely that Google will rank your site higher on the SERPs.