With proper API terms and conditions, brand guidelines, and requiring all developers to register a company can monitor and protect the quality of their brand.
By starting small, companies can get familiar with having an API and supporting the community that goes with it.
I recommend engaging with an API service provider like Mashery, Apigee or 3Scale when planning an API.
If you have your own in-house developers and want to keep development internally I recommend taking a look at Mashape.
Brands have to start somewhere. By starting with an API that serves up your core product data, you can take control of what information is available for your brand, while also learning more about building an API Community.
Once you have a simple RESTful API that provides product and location information, an API support area, and an awareness of what your developer community wants; you can then start innovating more around your brand API.