Subdomains are a way of creating separate accounts within your main account. It is accessed through a separate URL in the form of 'http://subdomain.domainname'.

This represents a sub folder within the public_http level of your account and you can create e-mail accounts with the subdomain extension.

Subdomains are often used to make the access to subdirectories easier by simply typing in a shorter domain name rather than the full domain name and directory names.

This allows you to point multiple domain names to the same website. For example, yourdomain.com, yourdomain.net and somethingelse.com can all point to the same location.

However,it can NOT point to a folder on the main domain. Additionally, it does not have any FTP features.

Notice that the price listed for domain pointers does NOT include domain name registration fees.

An addon Domain is a secondary domain name that points to a folder(subdirectory) within the main hosting account.

Example:
www.seconddomain.com will show the files actually in
www.maindomain.com/afolder/

An addon domain will act like a full account; you can create sub-domains, email accounts, and FTP accounts directly from the cPanel for your addon domains.

There will be no private cpanel logins for addon domains.

Notice that the price listed for addon domains includes domain name registration fees.