This article was originally posted on ClickZ.

I’ve heard it a thousand times – companies are afraid to add user-generated content to their sites. They’re afraid people will say negative things, that writers will go off-topic, or that, somehow, letting people contribute will hurt sales.

But there’s a big difference between “anyone can say anything on a site” and your “voice of the customer.” For example, anyone can say anything – no matter how profane, untrue, or damaging – on Facebook, Twitter, or YouTube. If your brand is referenced there, you have no control over what is said.

In the past five years, we’ve seen hundreds of brands overcome their fears of user-generated content. If you – or your management team – still fears user-generated content, here are some key principles to remember.

1. Most reviews are positive. In analyzing user reviews from hundreds of companies, we’ve seen that most reviews – up to 88 percent in the U.S., for example – are four or five stars out of a possible five stars. This percentage holds up worldwide and across a variety of industries.

2. All feedback – even negative feedback – builds authenticity. Including customer reviews on your site shows that you care about the direct input of customers; however, a site full of nothing but glowing reviews can make a shopper skeptical. Allowing a mix of positive and negative reviews proves to customers that you care about what they say – both good and bad.

3. “Bad” isn’t always bad. While some reviewers may rate a camera low because they believe the battery life should exceed six hours, others may not be so stringent. Qualities that matter to one consumer may not matter to all – or even most – consumers.

4. Reviews – even negative reviews – drive sales. Numerous case studies and client anecdotes prove that having any reviews has a positive impact over having no reviews. For example, QuickBooks lets customers review its ProAdvisors (experts businesses hire to help them use the software). It found that not only did ProAdvisors with reviews get more clicks than those without feedback, but the number of reviews was more important than the rating. For example, a ProAdvisor who rates four out of five stars but has nine reviews gets more clicks than a five-star ranked ProAdvisor with just two reviews.

5. Reviews let you know exactly how to improve your products. Sure, negative feedback can be hard to hear, but having reviews or Q&A on your site lets you aggregate what people think, quickly and easily – and you can respond directly to your consumers. For example, Domino’s Pizza recently made headlines with its “Pizza Turnaround” campaign, publicizing its decision to act on customers’ feedback to radically improve upon its 50-year-old recipe.

6. You simply cannot hide. Like I noted above, social networks are making it easy for people to share their opinions – and they’re doing it in real time. Ignore customer opinions at your own peril. Recently, when Consumer Reports gave Apple’s iPhone 4 a bad review, Apple deleted all references to the article that consumers posted to its discussion board. This prompted an outrage about censorship, which bloggers and other social network users brought to the forefront. So, what was really more damaging to Apple’s brand: a less-than-stellar review from Consumer Reports, or the censorship story that followed?

So, where’s the real proof that your brand shouldn’t fear user-generated content? The fact that financial services firms (one of the most highly-regulated industries) embrace the voice of the customer. Shawn Morton, director of mobile, social, and emerging media at Nationwide Insurance, gives his key to persuading management to add user-generated content to their site: “Tie it to clear business objectives,” he says. It isn’t enough to say something is a “fun, new trend.” Make the business case the old-fashioned way, just as you would for any other investment. Demonstrate the value behind social in numbers; show how reviews impact decisions. From there it’s easy to gain the executive advocates you need to make a case for social across your organization.