The Prediction API enables access to Google’s machine learning algorithms to analyze your historic data and predict likely future outcomes. Upload your data to Google Storage for Developers, then use the Prediction API to make real-time decisions in your applications. The Prediction API implements supervised learning algorithms as a RESTful web service to let you leverage patterns in your data, providing more relevant information to your users. Run your predictions on Google’s infrastructure and scale effortlessly as your data grows in size and complexity.
You can read more from the Google Labs Prediction API page
One of the cool things about this API is that it can be accessed from several apps:
Accessible from many platforms: Google App Engine, Apps Script (Google Spreadsheets), web & desktop apps, and command line
Plan to check it out and see how it compares with Open Calais from Reuters. Google is making it more and more compelling to use their APIs and App Engine.