An anterior pelvic tilt is when the top of your pelvis is tilted forward. This in turn pushes the butt out, curves the spine and affects posture and performance.
Here is a brief page on it
I realize that I have a slight to moderate anterior pelvis tilt. Having read a few articles by some powerlifters, they attribute poor utilization of glutes to being akin to having a pelvis tilt. Thinking to how I squat, I realize I get poor activation of the glutes. I never conciously flex them or feel that I have used them during squats, so I think my glutes aren't pulling the weight. My max squat is also lower for this.
Does anyone else have this problem? Was stretching of the hips and legs all you needed to correct it? Is there any concious thing I could add to my squats to better utilize my glutes?