Just as marketers increase their spending on social media marketing comes potentially discouraging news: consumers are trusting their friends a whole lot less.

According to AdAge, the 2010 Edelman Financial Services U.S. Trust Barometer found that only 25% of those surveyed considered friends and peers to be credible sources of information. That’s down from 45% in 2008.

The findings are stirring up a lot of buzz for obvious reasons. One of the reasons that social media is finally coming into its own as a bona fide marketing medium, where companies can interact with consumers and influence them through their friends and peers. But if Edelman’s findings are to be believed, friends and peers are just as prone to a crisis of confidence as the news media, for instance, which has also seen a precarious drop in trust according to Edelman.

That’s bad news for social media.

Part of the problem: the volume of information being distributed and how fast it is distributed. AdAge quotes David Berkowitz of 360i, who notes that consumers are flooded with information on popular social media hangouts:

When you’re seeing so much noise, it’s very easy to dismiss a lot of it, and that’s a problem marketing messages have had for a while now. If you use the live feed and have a few hundred friends, some kind of peer recommendation, whether it’s explicit or not, appears every couple of minutes and sometimes they come in a matter of seconds. If you’re seeing all of that come in, it can be overwhelming.

And it’s not just volume. It’s quality. As we see on a regular basis, the information that spreads through social media hubs isn’t always reputable, and social media makes it easy to spread misinformation for fun and profit. At some point, individuals are likely to remind themselves of the old saying, “Fool me once, shame on you. Fool me twice, shame on me.

But for marketers, the problem of information overload and a poor signal-to-noise ratio isn’t the biggest challenge. The biggest challenge is overcoming the fact that social media has been abused.

Lured by the prospect of sparking and controlling word-of-mouth, many marketers rushed into social media without thinking about the consequences of their strategies. From paid status updates to payola, one can be certain that a growing number of consumers are aware that their friends may be little more than corporate shills. In a day and age when someone will tweet a link for $50 or write a friendly blog post after being given some clothing, is it really any wonder that people are less trusting of their peers? Wouldn’t it be more surprising if these things had no impact on trust?

While I’m sure Edelman’s findings will be debated and even questioned, marketers should remind themselves of one fact: trust is earned. You can’t co-opt a ‘trustworthy‘ medium and expect to avoid this. Instead, you should take it as a greater incentive to use the medium wisely.

Photo credit: Hot Rod Homepage via Flickr.