RAM, which stands for Random Access Memory, is a computer storage media that is accessed much faster than a disk drive, as the info can be read randomly, skipping the bytes before the needed info is reached. On a hosting server, the RAM is used to load scripts and web apps after they are executed, so the more RAM you may use, the more programs you shall be able to run all at once and the more people shall be able to look through your sites without any effect on the site’s/server’s performance. Different from a disk drive, however, the RAM is used for non permanent storage purposes, due to the fact that the data is lost when the power is shut off. When you use a shared web hosting account, the physical memory which your scripts could use may be limited and can change according to what the some other clients on the same server use. Using a virtual or a dedicated web server, alternatively, you will have a guaranteed amount of RAM that will not be used by anybody else even when you don't use it at a certain time.