Today our algorithms rely on more than 200 unique signals, some of which you’d expect, like how often the search terms occur on the webpage, if they appear in the title or whether synonyms of the search terms occur on the page. Google has invented many innovations in search to improve the answers you find. The first and most well known is DA and PA, named for Larry Page (Google’s co-founder and SEO). DA and PA works by counting the number and quality of links to a page to determine a rough estimate of how important the website is. The underlying assumption is that more important websites are likely to receive more links from other websites.