According to this Slashdot thread, Wal-Mart has 460 terabytes of data stored on Teradata mainframes, at its Bentonville headquarters. That’s something like 249 if my computations are exact. That’s about 10,000 average hard drives (at 50 GB each) or 1,500 large hard drives (at 300 GB each). Suppose you want to store a matrix having 10 millions rows by 10 millions columns. Assume you store 4 bytes in each cell. That’s pretty much what Walmart has in storage. Another way to put it is that you can store 400 KB of data every second for 30 years and not exceed this storage capacity. If you had Walmart’s storage, you could pretty much make a video of your entire life. The Internet Wayback machine is reported to have about twice this storage.
One can only assume that storage will increase considerably in coming years. The impact this will have on our lives is still unknown, but the fact that gmail offers 1 GB of storage for free right now is telling: almost infinite storage is right around the corner and it will change the way we think about information technology.