Allow me to follow up on Tom's fine social media post with a word or two about marketing.

Word-of-mouth marketing is the most powerful force known to man. At least that's what we've been told for years now.

The conventional wisdom is this: People don't believe your advertisements or corporate communications … but if their friends say nice things about your company, they'll love you.

If you're a numbers person, let's put it this way: Only 14 percent of consumers trust ads, but 91 percent say they're “likely” to buy a product based on a personal recommendation.

Then came social media, and marketers just about wet their pants. “Finally,” they said, “here's a way to get huge numbers of people talking to each other about our products and services! We can't lose!”

More often than not, though, the marketers are the ones doing all the talking … and few people are paying attention.

For proof, check out the the 2010 Edelman Trust Barometer, an annual survey that gauges how strongly people trust businesses and government. According to the Barometer, the sources of business information that the public finds most credible are:

• Stock or industry analyst reports: 49 percent
• Articles in business magazines: 44 percent
• Conversations with employees: 41 percent
• News coverage on the radio: 38 percent
• TV news coverage: 36 percent
• Online search engines: 35 percent
• Newspaper articles: 34 percent
• Corporate communications: 32 percent
• Social networking sites: 19 percent
• Corporate or product advertising: 17 percent

So what does that mean?

The naysayers will immediately bellow, “Social media is a waste of time!” And in terms of an immediate marketing ROI, they'd be right.

As a marketing tool, social media is an amplifier: It sends your message to more people. And if people didn't trust your message before, well, it just means that even more people don't trust it now.

See, here's the thing: Social media isn't about marketing or advertising. It's about relationships. Hence the word “social.”

It's about building networks of people you trust. It's about sharing information that your followers find valuable, and following people who share information that you find valuable. When you do that over time (and I'm talking months, if not years), you build trust. Then, and only then, can you even think about selling yourself.

Without that trust, you're just screaming into a void.

Social media is not a magic bullet. It is not a quick fix. It's a deliberate, sometimes excruciatingly slow but ultimately rewarding effort to expand one's social network in professionally meaningful ways.

If you think you're going to achieve that by picking up a megaphone and screaming at your audience, you're woefully misinformed.