Twitter, Google, Blogger, Youtube, Facebook most of the famous networks excluding Hacker News make external links to open with a blank target. Opening links with target blank means the link opens on a new tab of your browser.
This leaves your page open and increases time on site so if you are tired of checking the box of ‘open link in new tab‘ or setting up target blank for each and every external link you add on your WordPress site then here is a quick solution for you.
LDB External Links, a WordPress plugin turns all your WordPress site’s links with target=”_blank” into rel=”external” and uses Javascript to open them in a new tab.
Although WordPress.Org says that this plugin hasn’t been updated in over 2 years. It may no longer be maintained or supported and may have compatibility issues when used with more recent versions of WordPress. Still, it is working just fine so you may give it a try. All you need is to install and activate it and you are done