Originally Posted by Justin Herring
Just to be clear, originality or value have nothing to do with trademarks (they are required for patents though). Trademarks are about brands. You can trademark a freaking bottle of water that is identical to tap water.
If Crossfit ends up like Pilates, it will be because the term has become a generic descriptor for a certain type of exercise, not because they are not original (or not effective, or not disclosed, or lacking in specificity, etc.).
This is explained here: http://en.wikipedia.org/wiki/Genericized_trademark
This is why Coke sometimes pays people to go around and make sure that other company's soda is not referred to as Coke. This is why I couldn't trademark "weightlifting!" as the exclusive brand of my new company.
CF Inc., according to someone who was within, has very little to no history of defending their mark and IP. I think you hit the nail on the head...genericide is likely to occur with the CF name.