On their About page, their Vision Statement: “Pachube (“patch-bay”) connects people to devices, applications, and the Internet of Things. As a web-based service built to manage the world’s real-time data, Pachube gives people the power to share, collaborate, and make use of information generated from the world around them.”
It 2008 Haque made released a framework that set up a way to “handle real-time data from sensors in interactive environments for his design practice.” This is another piece of the crowdsourcing movement, and the ability to track this much data and run it through this Pachube hub is very awesome. I guess in July 2011, LogMeIn acquired Pachube.
Anyway, Pachube used to be a paid service, but they recently (this month) made the service completely free for all users. An Overview of the Pachube API Documentation gives you a sense of how things work. There is also an API Quickstart that is useful if you know curl or hurl, command-line communication for scraping and posting data.