I suppose there's a difference between the "from the ground up micro-architecture" and "using a micro service or two" that should really differentiate the vario

I suppose there's a difference between the "from the ground up micro-architecture" and "using a micro service or two" that should really differentiate the various "should we use microservices?" discussions. Several sites I'm aware of have an Facebook-style chat service, which is basically an off the shelf node app on its own. This makes far more sense than trying to build such a thing into their legacy app. It also perfectly describes a very useful micro service, in a very different environment to yours.