Google co-founder Sergey Brin definitely stole the show at Google I/O today with a demo of Google Glass that involved skydiving, BMX ramping, and urban rappelling. But before that, the search giant showed off Google Now, a Siri-like app in the just-announced Android 4.1 Jelly Bean takes user search habits and gives answers to questions that haven’t even been asked yet.

Google Now makes use of the Google Knowledge Graph, the recently-added data engine that underpins the search engine’s ability to make inferences and go beyond the mere search string and get at the idea beneath.

But it combines it with Google’s often-creepy personalization algorithms to learn your habits and routines. For instance, if your favorite sports team is playing, Google Now will simply tell you the score when you pull it up. If you’re in a part of town you don’t often go to, it’ll provide ratings and reviews for nearby restaurants and stores. Or if your normal commute to work is traffic jammed, it’ll recommend a detour.

It’s pretty cool stuff, though I won’t be able to get my hands on it and try it out myself here at Google I/O for a little while. But it’s far more important as a milestone in the philosophy and practice of Big Data.

Google Now brings me back to the recent HBase Con 2012, where Cloudera founder and current Wibidata CEO Christophe Bisciglia discussed how he believes the next frontier in big data is personalization. Well, it’s arguable if this is the first example of that. But with 1 million Android devices activated every day, it’s almost certainly going to be one of the most prominent in what we’ll soon see as the next wave of consumer big data applications.

See, most of the conversation around big data is around business agility. If Company X lowers its price to Y, it sees Z percent increase in sales, and so on and so forth. But what something like Google Now does is add agility to one’s personal life, by taking these habits and behaviors and applying Google’s vast storehouse of data to help make more informed decisions in every aspect of life. It’s an open question whether we’ll find this approach more intrusive than helpful, but it’s early days yet.

In fact, this may be too bold a statement for these early days, but given the fact that the cloud is almost making the point of access into your data irrelevant, we may start to see BYOD come to mean “bring your own data” rather than “bring your own device.” A year or two or five down the line, we could start seeing these personal data trails start to become a common layer of interaction between the user and their apps, whether personal or enterprise. But again, that’s something that’s only going to become apparent down the line, if ever.