A Facebook Page Is Not A Website
While having a presence on the many social media sites is a plus, having your own website is important as well. Think of all of the pages on other sites as satellite offices and your website is your headquarters. Each satellite office does it’s part, but everything eventually flows through the main office.
Having a centralized location for customers to view you online is important, because it gives you more control over the content and also makes maintenance a lot easier.
Take a company newsletter for example, you post the contents of the newsletter to your main site and then post links to it from any others sites that you may want your followers to read it from. This allows you to attract more web traffic, but only create the content once.
I Already Have A Facebook Page, Why Do I Need a Website?