ptg16476052690 LESSON 25: Search Engines and SEO
and JavaScript) and store the contents in huge databases. This information is then recalled
later when a customer submits a search query to the search engine. Search engine com-
panies use complex, and secret, algorithms to determine which pages will be shown for
which search queries and in what order, or rank. There are often hundreds, possibly thou-
sands, of variables that go into the ranking algorithms, and each engine is different. But
some of them include
n Trust of the domain and domain quality
n Links to the site from trusted domains and sites
n Relevant content
n Length and readability of the content
n Engagement—how long people stay on the site after they’ve clicked from search
n Social metrics like tweets from Twitter or mentions on FacebookThese are not all the possible things your pages could be measured on when being ranked
by search engines. You’ll learn in more detail about how you can affect your search
engine rankings later in this lesson.Google
Google is currently the most popular search engine. Its search results are ranked based on
a secret algorithm known only to Google developers. Google is constantly updating its
search algorithm to improve its results for its users.
This search algorithm does a remarkably good job of pushing the most relevant sites
to the top of the search results. It also rewards people who publish useful, popular sites
rather than those who’ve figured out how to manipulate the algorithms that other search
engines use. Many sites that aren’t dedicated to providing search functionality use
Google’s index, so getting into the Google index provides wide exposure.
Google recommends that you focus on making your pages primarily for your users, not
for search engines. Your site should have a clear hierarchy, and every page should be
reachable from a static text link somewhere on your site. Sites that rank well in Google
tend to be information-rich and have accessibility features like alternative text on images
and descriptive title attributes on links. Google also recommends that your URLs
include keywords relevant to the page that are human-readable.