| traffic rank | Comparison between websites that reveals the number of visitors a website receives in comparison to all other sites on the Internet. |
| adsense | Contextual display advertising platform through Google. An automated process, opting into AdSense allows Google to place relevant ads on a website. Webmasters utilizing AdSense on their sites get a portion of ad click profits from Google. Contextual ads can be formatted as text links, graphics, animated graphics, and videos. |
| alt attribute | HTML code that provides information used by search engines and screen readers (for blind and visually-impaired people) to understand the contents of an image. |
| robot.txt | A text file that tells web crawlers which pages on a site should be ignored. This file should live in the /robots.txt folder of each domain. |
| metadata | Internal words that are stored in the html of webpages and are not visible to users, but are noticed in by search engine crawlers. |
