If you’re engaged in social media marketing, or considering it, you need to be aware of the top mistakes businesses make with this PR tool.

1. Having more than one face on the Internet. When you engage in social media marketing, you build your image from the ground up. The goal is to virally spread parts of your image across the Internet. The word parts is important. You start with a holographic image of yourself in the virtual world. You need to break that hologram apart and find the appropriate places on the Internet where you can frame certain pieces it.

When someone looks at all the pieces at the various sites, they should be able to put them together to see a single whole. They should not see multiple images of who you are, which would ruin your credibility.

If you have multiple Facebook accounts, for example, your personal one must be hidden and by invitation only. You don’t want that other image confusing people and possibly diminishing your reputation.

2. Collecting friends. SMM can create instant buzz on the Internet by getting the same message out over and over. It spreads your message and helps you brand yourself. Social networking, on the other hand, is about making friends. You’ve likely seen someone on LinkedIn who has 25,000+ contacts, but what do you do with 25,000+ contacts? Just because you have a phone book in your office doesn’t mean you can open it at random, pick a name, and call them for business.

When you collect a contact, you’re supposed to be opening the door to exchange information and build a relationship. Think of it as relationship marketing in the 21st century, and the same rules apply. The only difference is that you’re building the relationship online rather than over coffee.

3. Putting out the wrong messages. You’ve probably seen people put posts on Twitter or Facebook that say something like, "John Smith is watching a great movie and eating popcorn." Such messages may be fine for personal networks, but for business networks you need to put out messages that are useful to your readers. Don’t talk about yourself. Provide tips and advice so that the people who read your posts want to repost them to their own sites. That’s how your message spreads virally.

Keep your messages consistent. People subscribe to various feeds to get your information. They are essentially saying that your message has value. That’s why you can’t do a series of sales tips and then post your favorite omelet recipe. You have to stay on message, and your message has to be for your readers.

That said, it’s OK to occasionally have a press release-type message that says something like, "John Smith is speaking at ABC Convention on employee productivity today." Such a message does two things: It tells people they might not get a tip today or tomorrow because you’re busy, and it shows that others think your message is important. It’s a positive reinforcement that boosts your credibility, so long as you don’t do it too frequently.

4. Posting inappropriate information. Don’t allow yourself or anyone on your site to post anything online that you don’t want your most conservative client to see. You never know where something will end up, especially since the nature of the Internet is for things to spread virally. Consider the CEO who posted a photo of himself and his girlfriend on his personal invitation-only Facebook site. Someone thought it was a great picture and reposted it on the public Internet—where his wife (now ex-wife) saw it. His board of directors got wind of the photo and fired him. Never post anything on any site that you wouldn’t show your grandmother.

5. Assuming it’s better to have your message in only one place on the Internet. In the "old days" of the Internet, people believed they had to keep all their content on their own Web site. The theory was that spreading it out ruined your credibility and diminished your reputation as a unique speaker. Not so today. In fact, with SMM, the opposite is true. The more places you can get your message to appear simultaneously, the more effective it will be.

Think of it as constructing a funnel. You want to lay several trails of information, all of which lead to your main site. Therefore, no matter how someone stumbles upon you, as long as they follow the trail, they’ll eventually find you. That’s essentially what you’re doing with your Twitter and other SMM messages. You’re putting out kernels of information. If someone wants the next kernel, they have to follow the trail. Eventually it funnels them to one Web site, which is where you want them.

You’re creating an environment where people see your message everywhere. As a result, you now have their attention and the opportunity to sell your product and services at that point of distribution.

Here’s an example of the power of funneling: Recently Aaron Chronester posted a message on Twitter. Someone saw his post and reposted it on their blog. CNN and the New York Times found the post interesting and reported on it. Because of that exposure, Chronester got a book deal from Simon and Schuster. What was his post about? It was a Twitter post with a unique bacon recipe. Chronester was trying to get publicity for a barbeque club he belonged to.