Favicon is a shortened term for ‘favorite icon’, a custom icon (which is oftentimes a logo) that is associated with a website, appearing on the immediate left of the URL address in the address bar of your browser. It also appears on tabs in tabbed browsing, and is visible on the left side of bookmarked pages. Originally, it was Internet Explorer who introduced the use of favicons, and now other browsers support it, such as Firefox, Opera and Safari.
A favicon makes a website more easily recognizable and provides a viewer a visual cue on where to click instead of reading the text associated with a site. It is also a good branding opportunity for websites, because it allows for the reader to instantly view their likeness and associate it with the whatever the website is offering.
A fabicon is a very small file that must be saved as a .ico or a .png file in Internet Explorer. Once saved, this shold be saved in the root directory folder of your website. When your site is opened, the browser automatically looks for the favicon file, and once located, it is the displayed where it should be. Other browsers such as Google Chrome, Safari, Opera and Firefox allow other formats such as .gif and .jpeg files.