The Mention PHP Sample Code by Mention demonstrates API interaction. It presents code to obtain authorization, exchange code with access token, fetch account, and fetch alerts' list. See API documentation at https://dev.mention.com/
Many of the world's most successful technology companies have seen their fortunes bolstered by offering open APIs, but incidents last week involving Facebook and Spotify demonstrate that open APIs are not without risk, especially when enforcement of API usage policies is lax.
Here is an interview with Scoreoid founder and CEO, Almog Koren. Scoreoid allows you to gamify apps using the Scoreoid API and backend as a service. With 3000+ games and almost 1.8 billion monthly sessions- this is one API startup that seems to be going places.