I used to manage a few social media sites for a large corporation. Their basic practice was to first, have a presence everywhere you can. Second, stack the cards in your favor when things are public. Advertise publicly, solve problems privately in hopes that the satisfactory resolution becomes public, but not the details. For example: Customer comes in saying "You suck because xyz" Simply respond with "We'd like to make it better, contact us by way of bla bla bla" and do whatever you can to win that customer back. If they post back on your twitter/facebook that you rock, mission accomplished. If they post details, you don't want that kind of advert being made public as everyone will expect the same treatment. The only bad thing about having a social presence is that you almost need it to be monitored 24/7 because you're handing advertisement abilities over to your customers and random posters. Positive and negative adverts. If you're large enough that you have staff you can have check the social media sites at least every hour or two, then go for it. Make sure though that you're not just giving any ol' employee the ability the represent your company on Twitter for example. Terribly articulated responses make your entire business look bad. You're going to need to spend some time in preparing standard practices or policies regarding how you want the sites to run.
That's all I got for now, let me know if you have any more questions.
Humans are the only creatures that won't live up to the their potential. Give everything your all. When you die, die on E.
So I ask you, what do you intend to do now?