A web site is used to publicize and/or promote your business by putting everything from contact information to a complete description of your services on the web, you allow people all over the world to discover you, understand you, and contact you if they need your services.
Two of the most common types of web sites are information and personal. If you wish to share photos and stories from your family with relatives and friends, then your pages can be much more informal than if you are building a site to sell your services. If you are looking to build your business using the Internet, then your site should look professional since it will be representing your business.
In many ways, your site will become the first impression that a customer will have of your business, so it should look polished and as professional as possible.