The Hidden Technology That Makes Twitter Huge - Businessweek

Excerpt from a Twitter metadata overview

"You know how the National Security Agency collects “metadata” about the phone calls Americans make? Well, that’s what these fields are, except instead of metadata about phone calls, this is metadata about tweets. In fact, those 140 characters are less than 10 percent of all the data you’ll find in a tweet object. Twitter’s metadata is publicly documented by the company, open for perusal by all and available to anyone who wants to sign up for an API key."

The Hidden Technology That Makes Twitter Huge - Businessweek