stikkit

From their site: Stikkit makes organizing your daily details as simple as jotting down a note or firing off email. Stikkit's "little yellow notes that think" talk to the productivity applications you already use, as well as to friends, coworkers and family, giving you a universal remote for your life.
stikkit

Twitter

The Twitter micro-blogging service includes two RESTful APIs. The Twitter REST API methods allow developers to access core Twitter data. This includes update timelines, status data, and user information. The Search API methods give developers methods to interact with Twitter Search and trends data. The API presently supports the following data formats: XML, JSON, and the RSS and Atom syndication formats, with some methods only accepting a subset of these formats.
Twitter

GeoIQ

From their site: GeoIQ is a dynamic geospatial analysis and heat mapping technology that delivers high resolution raster analysis through a web browser. Developers can use GeoIQ to add geographic data visualization and analysis tools to their web mapping applications.
GeoIQ

Google Calendar

The Calendar Data API lets users perform most of the operations a normal Google Calendar user can on the Google Calendar website. Google Calendar allows client applications to view and update calendar events in the form of Google data API, GData, feeds. The Calendar Data API lets users incorporate Calendar functionality into their own application or website. Users can edit calendars, create and delete events, query for events that match particular criteria, send invitations, and more. There are many possible uses for the Calendar data API. For example, users can create a web front end for a group calendar that uses Google Calendar as a back end. Or a public calendar can be generated for Google Calendar to display, based on a company event database. Or users can search relevant calendars to display a list of upcoming events on those calendars.
Google Calendar

soundtoys

The site is intended to provide a meeting point for a growing community of artists and users, and in addition to the exhibition of audio visual projects, the site contains areas for artists interviews, links to resources, and texts by contributing writers where serious issues around interactive arts, audio visual syhthesis, generative art, and a history of interactivity are discussed.
soundtoys

YouTube

The Data API allows users to integrate their program with YouTube and allow it to perform many of the operations available on the website. It provides the capability to search for videos, retrieve standard feeds, and see related content. A program can also authenticate as a user to upload videos, modify user playlists, and more. This integration can be used for a variety of uses such as developing a web application allowing users to upload video to YouTube, or a device or desktop application that brings the YouTube experience to a new platform. The Data API gives users programmatic access to the video and user information stored on YouTube. This can be used to personalize a web site or application with the user's existing information as well as perform actions like commenting on and rating videos. This RESTful API provides responses in XML format.
YouTube

Spraci

Nightlife, clubs, gigs, festivals, arts, public events listings for many cities worldwide.
Spraci

Ning

Ning is a platform for creating social networks. The Ning REST API integrates with any Ning Pro account to import, export, and share data from apps running on Ning across the web or onto your desktop. Manage users, blog posts, photos, comments and other elements of your Ning Network. The company also has an API that supports the OpenSocial standard.
Ning

Plazes

Plazes is a location aware social network and search application. With Plazes, users can share their location with those people they want to know their location, while keeping their location private from those they don't. Users can also use Plazes to see what is happening near them and who is near them. The Plazes API allows developers to access and integrate the functionality and data of Plazes with other applications. Some example API methods include retrieving locations, accessing location categories, and retrieving user activities.
Plazes