RAM, that is short for Random Access Memory, is a computer storage media which could be accessed faster than a disk drive, due to the fact that the info can be read randomly, skipping the bytes before the needed data is reached. On a hosting server, the RAM is used to load scripts and web applications after they are executed, so the more RAM you are able to use, the more apps you'll be able to run all at once and the more people will be able to browse your sites without any effect on the site’s/server’s overall performance. In contrast to a disk drive, however, the RAM is used for non permanent storage purposes, since the info is lost as soon as the power is shut off. In case you use a shared web hosting account, the physical memory which your scripts are able to use may be limited and can change based on what the other customers on the same server use. Using a virtual or a dedicated hosting server, however, you will have a fixed amount of RAM which will not be used by others even if you don't use it at a given time.