A title tag <title> is the single most important on-page search engine optimization element on your site – behind overall content, of course! The title tag appears in three primary locations:
Browser – Title tags show up in the title bar at the top of your browser and in applicable tabs.
Search engine results page – Title tags also show up in search engine results.
External websites – External websites, especially social media sites such as Facebook, Twitter, Google+ and YouTube, will use the title of a web page as its link anchor text.
Title tag information also is used by search engines to index a web browser’s history information, as the default bookmark title and, lastly, as the text that displays in the back and forward button lists. (Hover over the back and/or forward buttons and hold down your left mouse button to get a list of sites visited.)