The article doesn't describe but one of the biggest difference is scalability. MongoDB supports horizontal scaling as a built-in feature. It's known that MySQL

The article doesn't describe but one of the biggest difference is scalability. MongoDB supports horizontal scaling as a built-in feature. It's known that MySQL can be scaled out by sharding but you lose ACID with it. Of course scalability is required only when the service goes well. But it's important to considerate it if you intend to be successful. It can be said scaled MySQL is a no-SQL. MongoDB is the New MySQL with this point of view.