Size and Network

• Domains can have anywhere from a few to thousands of computers within a single domain. Workgroups are typically small, comprising of fewer than 20 computers. Workgroups can be larger but their peer-to-peer nature make larger workgroups more difficult to administer. Computers on the same domain can communicate with each other even if they are located on two different logical networks while workgroup computers must all be located on the same logical subnet to communicate.
  
  

Administration and Security

• Each computer and user on the network has its own set of security permissions, which can be edited by a domain administrator. Individual files and folder permissions on domain computers can be set by a domain administrator. Workgroups do not have a central administration structure. File and folder security is managed on an individual computer level. For example, if you have administrator level permissions on your workgroup computer, you can set folder and file sharing permissions on your computer.
  
  

Users

• Domain users are created on the domain controller by a system administrator. If you are a domain user, you can log in to any computer on the domain, provided that your domain user account has permission to do so. If a roaming profile is set, you will even be able to keep certain application and desktop preferences no matter what computer you access on the domain. Workgroup users are set on each individual computer. If you do not have a login set on a workgroup computer, you must wait until a workgroup user with the correct permissions can create a separate account for you.
  
  

Usage

• Domains are often used in business environments where the centralized administration and higher security can help to safeguard critical data. For example, a large company may use a single domain to manage users from all over the world, allowing for people to share files, folders and network resources over a variety of interconnected local networks. Workgroups are often used in small offices or home networking situations where a small group of computers need to share data and network resources but do not require the complexity of a domain. For example, you can set up a workgroup on your home network to share data or a printer.