This is where you give a solid overview of your company, product, campaign, etc. For example: Social Network Announcement Page (SNAP) was created by Phillip J Rhoades (HowToPhil) leveraging the Bootstrap from Twitter framework. It is free to download, modify, extend, and use.
You can also embed the entire SNAP into another website (currently only in 300x300 iframe) and the CSS takes care of making it look good. Take a look here.
Download a copy of this site and modify SNAP (Social Network Announcement Page) to suit your needs. You'll need a decent understanding of HMTL, CSS, Javascript, etc, but it's a decent starting point.