One message – sent to just a thousand people – set off a firestorm last week, putting a major retail chain on the defensive and generating many negative media stories in the process:

The controversy began Wednesday when independent Chicago-based jewelry designer Stevie Koerner published a post on her Tumblr blog. The post showed photos of her World/United States of Love line, which she has been selling for two years on e-commerce craft Web site Etsy.com, side by side with Urban Outfitter’s I Heart Destination necklace line. The similarities were impossible to miss.

Her post said that when she saw the Urban Outfitters line, “My heart sank a little bit. The . . . line that I created is one of the reasons that I was able to quit my full-time job. . . . I understand that they are a business, but it’s not cool to completely rip off an independent designer’s work.”

Twitter latched on to Koerner’s blog post, and soon so many users were rebuking the clothing store for the supposed imitation that “Urban Outfitters” became a trending topic on the social networking site in the United States, Canada and the United Kingdom. Twitter users called it a “PR Nightmare” and a “smackdown.” (from the Washington Post)

This wouldn’t have been possible without the power of social media – and more importantly, the power of building the right network of key online influencers to help carry a message online.

Looking back at Twitter stats, I see that Stevie Koerner only had 972 followers on Twitter the day she sent the tweet that set off Urban Outfitters’ “PR nightmare.” That may not seem like all that many people. To put it in perspective: that’s about 300 more people than the population of Baraga in Michigan’s Upper Peninsula. How did a tweet sent to such a small number of people make such a major impact?

Koerner’s tweet blew up online because she had the right people following her – people influential in the fashion and design world who then had their own social networks of similarly interested people, and so on. Koerner’s initial message was retweeted hundreds and hundreds of times, as it filtered through different degrees of separation from her original account. The result? Urban Outfitters pulled the disputed item from all of its stores (and online) within 24 hours of Koerner’s first tweet.

This whole story underscores the importance of building strong relationships with key online influencers  – and how doing so can help or harm a brand or cause. Koerner’s network may not have been the largest, but it was very influential, which is how her tweet spread so fast. Building these relationships is not something you can do overnight, as it takes time to cultivate meaningful relationships with others online (just as it does offline), but will pay off in the long haul.

How do you find these key influencers? Look for who is already talking about your brand or cause online. Chances are, somebody is. The key is to be authentic: don’t just drop in, engage with somebody once, and then drop out. Building long-term relationships is the most important thing.

Try to put the same effort into networking online as you would offline (this being the week of the Mackinac Policy Conference, after all). You’ll find it will pay off. Just ask Stevie Koerner.