The Michelin Guide is a brilliant case-study in content marketing. It is as relevant today as it was at it's launch in 1900 and today's content marketers can learn much from many facets of The Guide.

The Michelin Brothers knew precisely who their audience was; the few, very wealthy people in France that could afford a car. They clearly thought hard about how they could be of value to their audience and published maps to navigate, restaurants to eat at underway and even a "FAQ" sections for changing tyres.

Finally there was a list of facilities to both service your car and purchase new Michelin tyres.

It's precisely the approach that works best today, delivering high-quality content that is of real value to your audience and building both recognition and reputation off the back of it. That you happen to inform your readers about your product in a way that is useful along the way is a by-product of addressing a need with your content. 

As a side-note, it's interesting that twenty years after starting the Guide, Michelin started charging for it's content. By this point, it's highly likely that accurate maps and other information was being produced by many publishers and Michelin needed to differentiate. Given that the Guide had to this point been a loss-leader that indirectly sold tyres, the decision to charge was not the obvious course, indeed quite the opposite could be argued. 

However, by charging, Michelin created scarcity and, by extension, bolstered the Michelin brand to being a premium product.