RAM, which stands for Random Access Memory, is a computer storage media that can be accessed much quicker than a hard disk, as the info can be read randomly, skipping the bytes before the needed information is reached. On a web server, the RAM is employed to load scripts and web applications when they are executed, so the more RAM you can use, the more apps you shall be able to run concurrently and the more people shall be able to explore your sites without any effect on the site’s/server’s functionality. Unlike a disk drive, however, the RAM is employed for momentary storage purposes, since the info is lost once the power is shut off. When you use a shared web hosting account, the physical memory your scripts could use may be limited and may change based upon what the some other clients on the same hosting server use. With a virtual or a dedicated web server, however, you will have a set amount of RAM which will not be used by anyone else even when you don't use it at a given time.