RAM, which means Random Access Memory, is a computer storage media which can be accessed considerably quicker than a hard drive, as the data can be read randomly, skipping the bytes before the needed info is reached. On a web server, the RAM is employed to load scripts and web applications after they are executed, so the more RAM you are able to use, the more programs you will be able to run simultaneously and the more people shall be able to surf your sites without effect on the site’s/server’s performance. Different from a disk drive, however, the RAM is used for non permanent storage purposes, since the information 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 can use may be limited and can change based on what the some other clients on the same machine use. With a virtual or a dedicated web server, alternatively, you'll have a fixed amount of RAM that won't be used by others even if you don't use it at a certain time.