The JotForm Python Sample Code by JotForm demonstrates how an API can help to print all forms of a given user, get submission of the latest form, get 100 submissions from the last date, filter forms by submission characteristics, and delete last 50 submissions.
PollDaddy, one of the most popular online poll and survey creation services, recently opened their new API to the public. The basic PollDaddy service provides free accounts for creating polls and surveys, or a Pro upgrade that eliminates sponsored links and allows higher numbers of survey responses than the free version. Now with the API, the core poll creation and reporting services are available to developers (details at our PollDaddy API profile).
Stack Overflow, the very successful question and answer site for programmers, have now released their own API into public beta. The API actually works with all of the Stack Exchange sites, including serverfault.com and superuser.com, with more sites possibly launching in the future. The API is supported by the site http://stackapps.com.