When I was a canine officer, I used to make fun of the idea of taking my dog to a dog park. Boy was I mistaken! Dog parks are just what the doctor ordered when it comes to socialization and exercise. You know you've hit the jackpot when it comes to visiting the dog park everytime you say those two words to your dog and his/her face lights up.
Socialization- the park becomes the perfect spot wher your dog can "act like a dog". He/she can explore the other's scents, wrestle, run, etc. It also becomes a place for it to to learn "the canine way" of resolving conflict. As long as there aren't a lot of doting owners handling everything their dog gets invoved in- then these dogs can settle things out for themselves. Now of course if there is an overly aggressive dog that is another matter and an owner would have to step in. But for the most part the dogs figure out when and how to submit to others and most will properly greet each other.
Exercise- just being enclosed in a large fenced in area is one thing, but add the other willing to run, wrestle and play dogs--it's a best scenario!
By the time you pull the plug and make your dog unwillingly leave, he/she is usually pretty spent.
Besides, the dog park is a good place to practice any obedience given the distractions e.g. call offs, leave it, be nice, come (although difficult), time-outs.
Information- I can't think of a more fun place to gain valuable information from all the different owners you will get to know. Afterall, we all love talking about dogs and all owners bring individual experiences to the table. Information sharing happens everytime I visit my local dog park.