In my opinion, Cross Fits greatest strength is its greatest weakness. When you have a team based approach with everyone encouraging each other (peer pressure) AND you measure all your workouts, it becomes very easy to overtrain. If you over reach on every session, injuries will happen as @bkreis mentioned.
It's documented in studies that Cross Fit does have a much higher rate of injury than other conditioning/strength sports. I've never heard of the term rhabdomyolysis (rhabdo) until Cross Fit became popular, but now I know people who've had it and they are Cross Fitters.
With the explosion of it's popularity, you can't deny it's appeal. Box owners/trainers are advancing their training curriculum to address these issue, so I would expect the incidence of injuries to decline and gain an even greater following.
As I mentioned before, I've never done cross fit, but do believe in the principles on which it's built. For Cross Fit or any other strength/fitness approach, moderate with various levels of intensity, listen to your body, and apply the same amount of rigor to your recovery as you do your workouts.