Although we have "the Internet" and "the Web", we may never have "the Grid".

Instead of having one massive "Grid", we have many smaller grids, each designed for a specific purpose.

National grids
National grids are hosted by one nation. A national grid gives a country access to huge computing resources. This is useful in emergency situations, such as earthquakes or terrorist attacks. National grids can also support scientific investigations, such as studies of climate change, space station design and environmental cleanup.

Project grids
Project grids focus on a specific goal. They are typically contructed from shared resources for a limited time and are designed to meet the needs of multi-institutional research groups and "virtual teams". The LHC Computing Grid (LCG) is an example of a project grid; it was set up to help with the LHC experiment in high-energy physics.

Goodwill grids
Do you own a computer? You can join a "goodwill grid". These grids are created when volunteers donate their spare computer capacity to a good cause. When you are not using your computer, a "goodwill grid" project can use it instead. Examples include the "@home" projects, where your computer can help solve some of the world's biggest questions.

Peer-to-peer grids
Users of peer-to-peer grids must give to get, exchanging data with other users. The now defunct Napster is an example of old peer-to-peer technology that required a central control (which is how Napster got nailed!); however, newer versions are truly peer-to-peer, requiring no third-party intervention.

Consumer grids
Users of consumer grids can rent extra computing power by paying the computer owners. For this to work, users need to find the specific resources they need, and be sure that they are secure. There have been attempts to use @home-type "cycle scavenging" to create a commercial consumer grid, but so far this is too unreliable to be a business proposition. Perhaps future processor chips could come with a grid facility preinstalled, to optimize their use by grids when not in use by the owner?

Private grids
Private grids (sometimes called local grids or intra-grids) are used by institutions such as hospitals and corporations. These grids are relatively small and centrally managed.