Ask HN: When does collecting data go from profitable to hording?

Everybody does it. Everyone collects data on their customers, advertisers, future customers - everybody. As hard disk space becomes cheaper, the amount of data being collected keeps growing. However, after all this data is collected, is anything useful coming out of it or is everyone turning into hoarders? Was there anything in human history that showed that exponential collecting old things ended up being profitable (other than for patent trolls, tabloids, and stalkers)?