Content on Website: Right Click Issue

I was visiting a website and trying to google from the website's words - you know with the right click of the mouse of the right away.
Then this screen displayed:


A guy told me if you have this feature on your website, it will load the page very slowly.
I don't even know what is the plugin/feature is it.

My gut feeling says it: It is based on Premium Content like insider or inner circle something.

Any pros and cons to have this feature on my...

Content on Website: Right Click Issue

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