Data Mining
There were 7 dwarves singing, "Hi ho, hi ho..." And then they evolved.
Data miners analyze large sets of raw, uncooked data (Think: Digital Sushi Bar) to look for patterns and correlations in order to predict outcomes or tailor marketing programs to the right customers. Like...you can send 12,000 banner ads for awesome hair conditioner, but if they all go to bald men (and women), you've wasted your marketing spend.
Loyalty cards at grocery and department stores are great sources for data mining. If they see you've bought pet food, either you have some weird proclivity for ground horse hoof, or you have, say, a dog. With the information collected from the cards, stores can then track who is buying what and at what price. Then they can specifically target marketing programs to send you coupons, for example, for products that you normally purchase. Social media companies also collect data on what sites their users are visiting and what products they are buying.
Data mining causes concern when the information collected is sold to other companies without the consent of the user. (Facebook, anyone?) Those with data mining skills are in high demand today, and for like another 20 years...until robots replace, well, pretty much everything.