You've set up a Facebook Page for your business and the number of Likes is growing steadily. This means you're free to market to these folks at will, right? Not so fast.
Just because someone Likes your Facebook Page, it does not mean he is asking you to market to him continually  via his Facebook news feed. A Like of a Facebook Page is akin to being someone's acquaintance. You know him and you may like him, but do you want to hang out with him all the time? Doubtful, until you get to know him better.
Even if the person hitting the Like button is a customer, that does not mean he wants to be explicitly marketed to via Facebook. Instead, he's hitting the Like button to signal an affinity for your products or services. That's a good thing. Don't ruin that by continually posting sales pitches that will turn him off and have him hiding your updates or un-Liking your Page altogether.
Now, I am not saying you can't market to these folks at all or should scrap your Facebook initiative. What you need to do is market to your Facebook fans without selling to them. Use content--shared blog posts, email newsletter articles, tips, photos, etc.--to draw them in and connect with them.
It's also imperative to remember that Facebook (and social media in general) is not a one-way pump for pushing information out to your connections. Start conversations with your fans on Facebook by asking them questions or have them share a story about how they use your product. They might have some tips on how to better use your product or service that would be helpful to other fans. Facebook is a great place for sharing this type of information. Once you start the conversation, don't forget to join in where appropriate to answer questions, offer encouragement, or just say "thank you."
So how do you know when a customer or prospect wants to be marketed to or sold something? When he calls, comes in, visits your Web site, or joins your mailing list. Those actions, unlike the click of a "Like" button, are surefire signals that a person wants to be marketed to.
As I've written before, social media Web sites are tools for accelerating the customer acquisition cycle . As you interact and share with your Facebook fans, you need a means for them to put their hand up to signal their permission to be marketed to. This can be a join my mailing list box right on your Facebook Page, a link back to your online store or Web site, or an invitation to come visit your store.
Don't disrupt the customer acquisition cycle by turning off prospects with overly aggressive sales pitches on Facebook. Nurture the relationship through good content and interaction, build a bridge from social media to your mailing list, and then market to those customers and prospects who have truly given you their permission to do so.