RAM is an abbreviation for Random Access Memory. This is a sort of computer memory, which, unlike other storage devices including harddrives or DVDs, allows the information to be accessed directly without reading the previous content located in it. Every time an app is launched, it is stored within the RAM, since it may be accessed considerably faster than if it was read from another media device. With regard to the web hosting service itself, additional RAM means that more web apps can run simultaneously on a particular hosting server, especially when they are resource-demanding and are accessed by a large number of people concurrently. Not like a shared web hosting solution where the system resources of a certain account may be flexible and often depend on what other users consume also, a VPS includes a guaranteed amount of RAM you can use all the time. That memory is assigned to one server only and won't be used by other customers even if it's not used.