These days, almost any small business should have a website. With costs being extremely low at the entry level, it's becoming difficult to imagine a reason for any company of any size not to have a website. Many user-friendly, free and open-source content-management systems are available to assist with Web design, so it is even possible to build a basic small business website without a professional Web designer.
Facebook is a great tool. It is free for a small businesses, but it is not a search engine. Because of this, most people would not use Facebook to search for a hairdresser or a plumber for instance. The majority of the public use Google when searching for things they need.
The Web has a far wider reach than any other form of advertising. While it takes time to build up enough traffic to your website to make a worthwhile impact on your company's marketing campaign, it costs next to nothing to do so. Your website will be the center of your company's online presence; through it, you advertise your business around the Web on social networking sites, forums and through pay-per-click advertising programs.
A website is online and accessible 24 hours a day, every day of the year. Because of this, your customers and potential customers can visit your site for support or information about new and upcoming products and services whenever it is convenient for them. Your website will act as an invaluable and always-available resource for information which would otherwise only be accessible during your company's business hours.
Your website can sell products at any time. Potential customers are not restricted to business hours. Instead, they can go online and purchase products whenever they want. A website with an online shop can provide a dramatic boost in sales.