RAM is an abbreviation for Random Access Memory. This is a kind of computer memory, which, different from other storage devices like hard disks or DVDs, enables the data to be accessed directly without reading the previous content located within it. Whenever an app is launched, it is stored in the RAM, since it can be accessed much more quickly than if it was read from another media. With regard to the hosting service itself, extra RAM means that more web applications can operate concurrently on a certain web server, particularly if they're resource-demanding and are accessed by a large amount of people at the same time. Different from a shared web hosting package in which the system resources of a given account could be flexible and often depend on what other end users consume too, a VPS has a guaranteed amount of RAM which you can use always. That memory is allotted to one hosting server only and will not be used by other clients even when it's not being used.