Some businesses need large amounts of bandwidth to the Internet to accommodate the popularity of their website. Other businesses are very sensitive to security issues due to ongoing web commerce applications, and want the absolute security that owning their own server affords them. You can better support the speed and reliability of websites with large traffic volumes. Your website performance won't be affected by other websites' sudden traffic surge. Most virtual web servers and virtual host websites share servers with other webites.
Some providers put hundreds of webites on one server.
Your website will be more secure. Only you and Netsville staff can access your dedicated server. Your site won't be down because someone else is running a flawed or buggy CGI program on his website. When on their own machine, customers can tweak the server however they like. Customers are not limited by the restrictive rules of processor and bandwidth sharing inherent to shared hosting solutions.