The Difference Between a Shared and a Dedicated IP Address
Every domain name that is a home to a website has an IP address assigned to it. An IP address is the real address of a website. Domain names were developed because it is difficult to remember long IP numbers like 220.127.116.11.
A shared IP is an IP address that is used for multiple sites. A shared IP can host all sites on a webserver. Because the IP address of a website is used for various sites on the server the actions of one site owner can affect everyone on the server. For example, if an IP address is blacklisted for spamming this will blacklist mail for all sites using the shared IP address. We work hard to prevent and to resolve these issues immediately and take corrective action against anyone who abuses the system. You will not be able to install an SSL certificate if your site is on a shared IP.
Many site owners are able to host their site on a shared IP without ever being affected by another owner on the server. If mail is critical to you we recommend using a mail hosting provider that can provide a robust mail server such as Google Apps. This will also help you because if the shared IP address becomes blacklistes your email will not be affected because your mail will be hosted elsewhere. Google Apps is able to offer more mail storage and better spam and junk filtering than the service that is available with your web hosting account with us. For instructions on configuring Google Apps please read How to Configure Google Applications.
A dedicated IP is an IP address that is assigned to one site. Large websites or e-commerce sites have dedicated IP addresses that host only one domain. If a site handles payment processing directly and not through a third party such as PayPal, the site must use SSL and therefore will need to be on a dedicated IP address.