OK, I have this design problem I've not been able to find a good answer for.
Let's say you're tracking customer pricing for a widget. Now, widget prices are volatile, changing weekly or even daily. And you need to be able to go back in time and say "on this day, we would have charged you 5.32 yaks for a widget". So, you set up a table that has a price, a "price start date" and a "price end date". When you quote a price, you need a date, and you can retrieve the price.
The New York Times is running an article that got a mention on Slashdot about Dell's entry into the print business. The article, found here pretty much relates everything that I hate about Dell and admire in companies like HP. The money quote from Dell:
"The days of engineering-led technology companies are coming to an end," Mr. Dell declared.
Which is unfortunate, because without engineering-led technology companies, there is no innovation.