There are two fundamental ways that the search engines use links:
- To discover new web pages
- To help determine how well a page should rank in their results
Once search engines have crawled pages on the web, they can extract the content of those pages and add it to their indexes. In this way, they can decide if they feel a page is of sufficient quality to be ranked well for relevant keyword. When they are deciding this, the search engines do not just look at the content of the page; they also look at the number of links pointing to that page from external websites and the quality of those external websites. Generally speaking, the more high-quality websites that link to you, the more likely you are to rank well in search results.