Twitter

Social media. Provides a handful of different APIs.

API

A REST API with JSON output. Needs an API key, by using an OAuth consumer key.

Documentation: https://dev.twitter.com/

The Streaming APIs
The set of streaming APIs offered by Twitter give developers low latency access to Twitter’s global stream of Tweet data. A proper implementation of a streaming client will be pushed messages indicating Tweets and other events have occurred, without any of the overhead associated with polling a REST endpoint.

https://dev.twitter.com/docs/streaming-apis