As a business you cannot ignore this anymore. In order for a business to succeed today and grow they need to take advantage of these new Social Networks. Businesses use twitter and Facebook to promote products and enforce their brand, to reach out to and connect with customers. You can use LinkedIn on the other hand to connect and network with other businesses and professionals. So how do you take advantage of these Social Networks on your site?
Make your website share-able - add social media buttons to your home page including Facebook "recommend" or "like" buttons, a Google+ button, A tweet button. Convert website visitors into customers. Start a Blog and connect it with your website.
Bring people to your Facebook page. This is an easy way, with a single click, they tell all their friends about you. Point them to you Twitter page and have them follow you (A great way to tell all your customers about new products, services or discounts going on right now). Convert website leads (not a customer but is interested in your product or service) into clients.
Have an App that runs in Facebook where people can look at and get information on your product or service without leaving Facebook. (As of April 2012 - People on Facebook install 40 million applications every day)