Ok, forgot about this post for awhile, but here's my response. I'm not talking about taking balls out of the air while standing on the baseline, I'm talking about stepping into the court and snapping off a shot inside the baseline. It takes away time from your opponent. Right now lots of players do this off short balls that would otherwise be volleys or approach shots. What I'm talking about is taking this shot a little further back and hitting it off balls that would land 2-3 feet inside the baseline. I've seen Agassi do it, but it takes very fast feet and acceleration. Give it a try next time you get a deep floater, it's a pretty effective shot that will catch your opponent off guard.