During the boom years, technology advances were generally viewed in terms of how they allowed us to do new things.

Check out this new gadget - it lets you play a video game while skiing! It lets you update your Facebook page while scubadiving! It lets you Twitter while visiting the john! Awesome!

But there's another side to technology that maybe hasn't got enough play, but is likely to as the economy gets worse.

New technology also lets you do all the same things you always did, only cheaper.

And it's not just a matter of comparison Web sites like billshrink.com that help you cut costs.

TV Web sites like Hulu.com will let many people save money by canceling some of their cable TV package. High-speed wireless Internet, from 3G to new WiMax, should let them save on home Internet connections. (Xohm, the new WiMax service, is priced well below cable- though at this point it has only been launched in Baltimore and rollout to other cities is taking time.)

Voice over Internet lets you dump your landline, and maybe even cut back on your cellphone. Google Talk lets you make video phone calls to family, friends or colleagues around the world for free.

New electronic book readers can give you access to discounted books and magazines. Amazon's Kindle is only the best known. Several can be used to "borrow" electronic books, complete free, from the public library.

At first blush, the individual savings seem too small to bother with.

They're not.

Ask yourself if it's worth changing cable or home Internet providers, say, or cellphone providers, in order to save just $10 a month.

Many people couldn't be bothered. It's no surprise. Ten bucks doesn't sound like much.

But one of the key themes of this column is that combining recurrent savings with compound interest has explosive power. It's the atomic fission of finance.

Slashing just $10 from each month's costs and investing it, instead, adds up to quite a bundle over the course of an adult lifetime. Someone who did that over fifty years would have an extra $54,000 when they retired. Not bad.

Until recently, few people thought like that.

Just ask the people around you how much their cellphone or their cable TV package costs them. Chances are they will just quote you the price per month as if it's the total cost. "Oh, my cellphone's only about $70," they'll say. Or: "We only spend $100 on cable."

The true cost, year over year, is vastly greater.

It's something worth thinking about in relation to the technological wizardry that permeates our culture. The real value of these whiz-bang innovations isn't that anyone can live blog the presidential inauguration that everybody can see on their TV set anyway. Used wisely, these tools can put more money in your pocket.