Social media is the future.
As far as the complaining, if you're a business owner, don't ignore this or even look at it negatively.
Use this as a chance to redeem your business directly to the customer. And if not, at least you know what you are doing wrong to improve your business practices.
Think about it, by simply addressing concerns people have you are making your product or service better and better. And for you small businesses, this might save you time and money on doing surveys.
"But people keep posting all negative feedback, I know some people like my product"
Recommend that satisfied customers post their positive experiences on your Facebook or Twitter page. Possibly offer some type of coupon or other incentive to have people remember to post their experience on your page.
Point is, social media is NOT going away anytime soon. Jump on the bandwagon and harness its power.