Well, if a couple is sitting on a bench in a mall and they're talking, rummaging through bags to consolidate their purchases, and they turn for a quick kiss, that's PDA. If a man is walking with his girl and the girl reaches over and wraps her arm around his waist, that's PDA. If two people are naked in the mall's fountain getting love juices everywhere, that's PDA.
I don't mind seeing people kissing. I do mind watching people in public who don't have any regard for anyone else and are tonguing eachother's tonsils. Come on, folks...
But, then again, I know what it's like to really really really miss your significant other and when you finally see them after months of being away at college, and you can't help but give them a huge hug and kiss right in the middle of the airport. That I can understand. But when it just starts getting out of hand for no reason other than blue balls or something like that, that's where I draw the line.
nik