RAM is an abbreviation for Random Access Memory. This is a sort of computer memory, that, different from other storage devices such as hard disk drives or DVDs, permits the info to be accessed directly without reading the previous content saved within it. Every time an application is launched, it is stored in the RAM, as it could be accessed much faster than if it was read from another media. In terms of the web hosting service itself, additional RAM means that more web apps can work simultaneously on a certain hosting server, particularly when they're resource-demanding and are accessed by a great number of of people all at once. Different from a shared web hosting plan in which the resources of a given account may be flexible and often depend on what other end users consume also, a VPS includes a guaranteed amount of RAM you can use at all times. That memory is assigned to one web server only and will not be used by other clients even if it's not used.