Puppy preschool or kindergarten is a great avenue for socialization with other puppy dogs of a similar age. However, the discord comes from the question of puppy vaccinations "could it be safe to have a puppy out during this time period?" This is a problem because on the main one palm you want to teach your pup to be sociable but keep carefully the puppy safe at the same time.
Puppy socialization can also include making funny faces and stupid sounds at puppies; exposing these to skateboards, bikes, wheelie bins and other moving things. Sounds of airplanes, loud equipment, children screaming, infants crying, radios blaring are generally every day occurrences that your pup may experience in later life. CD's are available with all sorts of sounds, including thunder which is something that's not always available for the dog to get accustomed to.