The #1 danger to your API's usability is the half-assed implementation a 3rd-party will release to the public without your prompting or involvement. Don't let that happen. Take initiative and release libraries for as many languages and frameworks as you can, or risk the danger of being sabotaged by someone's indifference, or most likely incompetence.
You can't believe how many time I have had problems with an API just to discover the 3 year old client library was using some "sensible defaults" for required arguments.
You can't believe how many time I have had problems with an API just to discover the 3 year old client library was using some "sensible defaults" for required arguments.