It may seem cool to have a tough, vicious dog, but that dog is only a liability. Dogs need to be introduced to as many, and as varied an amount of people as possible at a young age. This will not ruin the dog's protective instincts (if the have them). What this will do is create an animal that can be in the house with guests, that can be taken into public without embarrassment, and will decrease the chance that someone's unattended child will cause you a lawsuit and the loss of your pet.

Socialization is easy in these days. Go to PetsMart or PetCo. There will be dozens of people that would like nothing more then to gently rub your puppy and show it that people are good.

This is also another time that you can increase your dogs understanding of the world. The more a dog goes out as a puppy, the more relaxed it is as an adult. You won't have a wildly frothing, pulling animal every time you leave the house because it will already understand and accept these things as normal. Every sensation will not be new and strange.