Couple of interesting answers on Quora, but this part from Michael E. Driscoll’s answer is quite interesting:

You could even get 100s of daily TBs of data yourself:  if you can afford the network bandwidth fees, there are ~100 marketplaces (Twitter’s MoPub, Google’s AdX, Facebook’s FBX to name a few) that surface approximately 200 Billion advertising auctions per day.  You can build a bidder, get a seat on their exchanges, and make millions of daily trades — you’ll just need to convince a brand to act as their broker, and take your 20% cut of spend.

Original title and link: Which companies produce more than 10TB of data per day? (NoSQL database©myNoSQL)