That's from exceeding the stress tolerance of the part, not from fatigue. Those are completely, totally different things. You can break a new part if you subject it to enough stress.

A question to those who think that frames should be retired - are we talking about the joints cracking, or the tubes failing? I'd me much more worried about the joints cracking than a tube failing. Compare bikes to other structural applications of aluminum. The pittance of ride time experienced by an aluminum frame is nothing compared to rigid members in an airplane, which can see near constant use for decades without being retired.

Now, if you're talking joints...well, that's why structures exposed to heavy loads aren't welded. But cracked joints can happen to modern frames too. At some point, you have to accept the fact that parts on your bike can fail. One solution is to actually wash your bike so you're more likely to see little cracks. Also track down mystery noises that might be coming from a cracked joint.

But if the OP has a light, high-quality vintage aluminum frame with low miles that he just doesn't feel right riding or selling after reading this thread...send it to me, I'll cover postage.