Start a blog on how your company is helping to make the world a better place and link it to your web site. Celebrate your employees and/or customers by creating a Flickr photo gallery (what about testimonials?!) and hyperlink it your your site. Post interesting videos on You Tube and feed them onto your site...either as an extension of your company's core messaging or to add value to your brand with human interest "sidebars."
To get started, get your entire team together, and I mean the WHOLE team. When it comes to social networking, everybody has something interesting to say and can help stimulate your collective thinking on what features and special attributes will help make your web site a true destination for interested web visitors. Have fun with it. Be creative. And don't discount any idea throughout your brainstorming process. You just never know where the next "big idea" will come from.