Social Media sites such as LinkedIn, Twitter and Facebook continue to explode in popularity. If Facebook (over 200M members) were a country it would be the sixth most populous on the planet and rank between Brazil and Indonesia. Many people are asking what social media has to do with business. From my perspective the answer is "plenty." Following are a few examples of how business can use social media.
 
You can investigate employment candidates or current employees.  What a person reveals online can tell you about who they are and their attitude towards work.  A blog, for example, reveals a person's thinking and communication skills.  If a job applicant is part of LinkedIn you can review their employment history and online recommendations.  

You can monitor the activities of your competition and other companies in your industry. Social networks are a great tool for generating buzz (see below) about a program, product or initiative and, as such, are probably being used by your competition and other companies in your industry to promote themselves. So use the social networks for intelligence gathering and learning about your competition and your industry in general.

You can network with individuals and businesses using social networks to foster cooperation, build partnerships and locate new sources of products and services. At times social networks can feel like one big Chamber of Commerce mixer, with everyone trying to sell their products and services to everyone else. That can be annoying when you're not looking to buy anything but it's also a good way to become an informed consumer.

You can speak directly with customers on a more personal level through social networks. A lot of busy executives no longer have the time to visit customers regularly, social media is an excellent way for them to hear the voice of the customer without having to travel or have the information filtered through sales or marketing. Social media can also be used to address customer concerns directly and prevent minor issues from becoming major problems.

You can use social media for low cost viral marketing. Two fantastic things about social media are the low cost and the multiplier effect, a friend tells a friend who tells a friend, and so on. A simple website on Twitter can be used to spread information rapidly, generate sales and build a network of loyal customers. Similarly, companies test market product designs and marketing campaigns all the time. They simply float an idea and collect all the reactions before making a final decision. Politicians do this regularly.

You can use social media as an extension of your customer service efforts. Dell does an excellent job of using Twitter. They have several accounts - Direct2Dell, Dell Cloud Computing, Dell Small Business and Dell Your Blog - and each one is targeted to a specific audience using a specific Dell product.

You can use social media as an online classroom. There are experts in virtually every field online. Use social media to connect with them, ask them questions and learn new things. In exchange, of course, they're going to want access to your area of expertise as well.