Semantics. That's what many will say. They'll tell about how trying to define the difference between being a marketing platform and being a marketing tool is pointless.
Others will say it's much more of a platform for marketing than it is a tool. They'll say that it's the community and the venue that offer the benefit and trying to corner Facebook into a toolbox is unwise.
Both, in my humble opinion, would be terribly wrong.
When looking at Facebook as a platform, we see certain elements that stand out. It's huge - a billion users can't be wrong, right? It allows businesses to create pages and market their wares on these pages and within the news feeds of their fans. It allows apps which can be used to do nearly every business operation directly from the platform. With all of this evidence, it's clearly a marketing platform, right?
This is the biggest mistake that many businesses make on Facebook. In many ways, it's a trap, and the majority of businesses who look to Facebook fall into that trap.
Facebook wants to be a business interaction platform. It wants to be a marketing platform. It wants businesses to look to it and (in some cases) pay them money to get their merchandise and services exposed. The only thing stopping them (other than poor decisions regarding business since 2009) is that the power of Facebook, namely the people, want nothing to do with it.
This is the key point that businesses must understand. It's the point that steers Facebook away from their unstated goal of being a marketing platform and towards the unfortunate reality that they are a tool in an overall content marketing strategy. Through Facebook, a business is better served promoting the things that are not necessarily "business focused" in order to gain favor with the Facebook algorithm. They can (and should) do this through ads, but the reality is that a business must be willing to interact with people and engage with the community before they can have any chance of getting marketing benefit from the site.
Once this is done through any of a dozen groups of techniques, it now becomes possible use the tool for marketing that Facebook truly is. It's a tool in a toolbox that includes LinkedIn, YouTube, and, of course, the four majors of today (which can change at any time).
Businesses must understand this distinction. They must learn that what happens on their Facebook page is minuscule compared to what happens off their page, that what they say is meaningless compared to what others are saying about them, and that to make their message work, they have to get involved rather than put themselves into a box.
Platforms are boxes. Tools lead to the freedom to explore.