Today you can buy a one-terabyte Seagate drive online for $80, shipping included.  That works out to about 8 cents per gigabyte.  In August of 2003, I paid 80 bucks for a 120 GB drive:  about 67 cents per gigabyte.  If you adjust for inflation, I got eight times as much storage for about $10 less money.  According to The Inflation Calculator, $80 today is about the same as $70 in 2003.

So how much is a terabyte, really?  If you’re into music, you can get one million minutes (694 days) of music on a terabyte drive, assuming a megabyte a minute (reasonable quality MP3).  VCR quality video is about 10 megabytes a minute, so you could get about 70 days of video.  DVD video is quite a bit more expensive, but you could still store 500 two-hour movies on your terabyte drive.

So what else can you do with a terabyte?  Consider:  human speech is historically recorded at 8,000 samples per second, requiring about 64 kilobits per second.  Current compression techniques can drop that to 8 kbits/sec with almost no perceptible loss in quality.  Figure one kilobyte per second.  A thousand seconds per megabyte.  A billion seconds in a terabyte.  How long is a billion seconds?  Google calculator says 31.69 years.

Imagine somebody with a voice recorder that’s always on.  Everything he says or hears is recorded and stored.  Furthermore, he has a program that can go through the recordings and create a phoneme transcript of every conversation.  That’s possible with current technology.  It’s even possible (with some errors) to identify individual speakers (i.e. Speaker 1, Speaker 2, etc.)  With a little human input, the program could identify speakers by name.  A little more work, all with technology available today, and a person could have a database of tagged transcripts containing every conversation he’s had.

I don’t know about you, but I’m a little uncomfortable with the idea that everything I say is subject to being recorded without my knowledge and reported at some point in the future.  Worse, given enough samples, a person with evil intent could easily construct a very convincing version of me saying things that I never said.  I don’t think I’m worth all that trouble, but there are plenty of people who are, and who perhaps should be somewhat concerned by the possibility.