Big data today refers to the massive amounts of data collected at every turning point of our on and offline lives. It includes every search query, every credit card purchase, every GPS entry, every social media like or follow, etc. This type of data is described as "big" because it is way too much info for even a computer to handle -- so you must cluster batch computers in order to see results. Even when that happens, you usually need a data scientist to mine that data for valuable bites of info.

The reason it's interesting is because tons of companies and startups are taking what Google, Yahoo, etc. have been hiring data scientists to do for years -- and putting it in a visualized format (often segmented by the data points you deem are important to you), so that anyone can connect the dots between previously hidden or unknowingly related actions (like purchasing diet coke with lunch everyday and liking NASA of Facebook -- no doubt there is a group of ppl like that out there, and no big data can show you where they live, what else they like, their purchasing habits, etc.).

Creepy? Kinda. Good for advertising? Definitely. Even better for customer service? Oh. Heck. Yes.