This is really a no-brainer. If you are offering API you want to make it as easy as possible to adopt and implement. However, perhaps it is advisable to go even one more step beyond providing "starter projects" and suggest actual use cases. They could be implemented in those starter projects (best case) or simply illustrate the utility / value of the API. Don't just rely on 3rd party developers to figure out what to do with your API - provide guidance of what you might want to see them do with it.
Bootstrap is unique because not only does it provide an API (the javascript link is at the very top of the page), but you can view the source of any segment and see very well documented code samples.