RAM is an abbreviation for Random Access Memory. This is a sort of computer memory, that, in contrast to other storage devices such as hard disk drives or DVDs, permits the information to be accessed directly without reading the previous content saved within it. Every time an application is started, it's stored within the RAM, as it could be accessed considerably faster than if it was read from another media. With regard to the website hosting service itself, more RAM means that more web apps can run concurrently on a certain web server, especially when they are resource-demanding and are accessed by a large number of people at the same time. Different from a shared web hosting solution where the system resources of a given account may be flexible and quite often depend on what other end users consume too, a VPS provides a guaranteed amount of RAM which you can use at all times. That memory is allotted to one hosting server only and will not be used by other customers even when it is not being used.