Quasi said:
It's for steep gradesQUOTE]
ECC is a crutch. And it messes up your bike's handling. Proper bike setup (saddle positioned far enough forward) and proper body position (scoot forward until the saddle nose is trying to violate you, bend your elbows like you're at the bottom of a push-up) are the right way to climb a steep grade. I'm on my 4th fork with ECC, and I always use it about 5 times on a new fork and then never again. Also the RockShox remote lockout levers are horrible horrible horrible. The ones I tried were impossible to adjust properly (4 very talented bike mechanics couldn't get it to work), and it would gradually slide back to lock-out-position while riding. Maybe it works better now, but the whole bar-lockout-idea needs a few generations of refinement.
Well, when we run 5" and 6" travel forks because we like going downhill, we can't avoid the fact that we have a very high front end that is going to wander around. As much as you want it to be, a high front end will ALWAYS wander around, be harder to control, and require more effort to climb a hill than a lower front end like found on an XC bike.
So, we have ETA which locks our forks down to give us steeper head angles and the same axle to crown height of an XC fork or less.
And just like it helps freeriders, it helps XCers when they can drop their fork significantly to help them gain more leverage for a climb.
No body position or setup can totally make up for the fact that a high front end is a high front end and a b*tch to get up some hills. ECC can be pretty crappy though, because it locks it out as well, and seems to "stall" over rocks easily because it is essentially "rigid", this is where ETA comes in, it doesn't "stall" over the rocks like ECC does.