RAM is an abbreviation for Random Access Memory. This is a kind of computer memory, that, unlike other storage devices such as hard disk drives or DVDs, permits the data to be accessed directly without reading the previous content located within it. Anytime a program is launched, it's stored inside the RAM, as it may be accessed much faster than if it was read from another media device. With regards to the hosting service itself, more RAM means that more web applications can work concurrently on a certain web server, especially when they are resource-demanding and are accessed by a large amount of people simultaneously. Not like a shared web hosting plan where the resources of a given account could be flexible and frequently depend on what other end users consume as well, a VPS offers a guaranteed amount of RAM which can be used always. That memory is assigned to one server only and shall not be used by other customers even in case it is not being used.