On one side it can be an easy way to find new patients, on the other side it is an easy way for disgruntled patients to spread the word of their bad experience.
Since there isn't a way to remove all negative feedback from the Internet you can at least fight back.
YELP: You can comment on reviews- something to the effect of we are sorry that you had a bad experience this is not typical in our office- we are attempting to contact "Mr. Smith" to make this situation right.
MyBodyNetwork: This is an Internet platform that allows your patients to post "success stories".
It also serves as a referral network for your patients to specialists that you know and trust. And includes the ability to post relevant information in the news section and video clips. This site can link to your website or can be used as a stand alone site if you don't have a website, it will help increase your Internet exposure and eliminate the concern of negative feedback