The Twitter Node.js Library by René Raab is a simple module that allows developers to integrate the Twitter API's methods into their Node.js applications.
While there may not be as much buzz about OpenSocial right now as there was at launch, lots of progress is being made by folks inside and outside of Google.
Online stalking has gone programmatic. People search engine Whoozy has a person search API. With it, you can get results for a name from social networks and blogs, in addition to standard search engines.