Parts fail.
The link posted by hollister shows components made by Race Face, Tioga, Colnago, Bullseye, Shimano, Grafton, Topline, Stronglight, Truvative, GT, Fox, Easton, Cannondale, Specialized.. and on, and on. Some steel frames, some aluminium. Do we all just stop riding on these manufacturers components now?
I guess this links in with the discussion about the Chi-Ti forks elsewhere on here. It is easy to post a pic of a component and say "these fail, don't ride 'em" but in reality the failiure rate is probably very small and whilst a healthy dose of 'respect' for lighter parts may be required, lets not get paranoid, if we stopped riding on every part that someone had broken in the past, we'd all be walking.
We also don't know the 'real' reason for the failiure of any given component. I've not ridden with anyone yet that uses a torque wrench to make sure that manufacturers tolerances are applied, but I have ridden with lots of people who have broken something and then given the LBS some b*llsh*t to make sure that they got it replaced under warranty.