Here's why you should care about this: as CPUs get faster, they also get smaller while packing in more transistors. That's great for speed and processing power, but it makes cooling tough. CPUs generate more and more heat over ever-smaller surface areas, so dissipating that heat is progressively more difficult. Not pretty.
And if you overclock your processor, you're just making it worse.
How much worse?? That's where the ol' dissipation table comes in. Look up your CPU, voltage, and clock speed, and find the wattage per square centimeter to find out how tough it's gonna be. Walk up the chart a bit to see how overclocking will change the math. Currently, the 1.33GHz T-bird gets the "blowtorch on the head of a pin" award. Check the table to see where you stand.