Twitter's stock is soaring today as it opens to public trading for the first time, but the reason why investors are so excited about the service isn't just its 140-character messages. In an exploration of the technology that makes Twitter so valuable, Bloomberg Businessweek details the wealth of metadata hidden behind every tweet. That metadata allows a tweet to tell far more than it initially appears to, even constructing an entire story about its sender. A tweet might include the precise coordinates of where it was sent, a name for the location it was sent from, the time of day, whether it includes sensitive content, and much, much more.

While those details may sound basic, they're what allow Twitter to effectively sell its advertisements. For one, the data can help pinpoint how an individual user interacts with Twitter. It also allows advertisers to get a sense for how larger groups of people use the service, helping them decide when the best time to send out an ad might be. In 2010, one Twitter engineer broke down exactly what all that data behind a tweet looks like, pointing out exactly where it's all hidden within the code. Using that data hasn't been enough to make Twitter a profitable success just yet, but investors clearly expect that there's enough data and enough users there to turn it into an advertising powerhouse.