RAM, that is short for Random Access Memory, is a computer storage media that could be accessed much quicker than a hard drive, as the information 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 programs after they are executed, so the more RAM you may use, the more programs you'll be able to run all at once and the more people shall be able to browse your websites without any effect on the site’s/server’s overall performance. In contrast to a disk drive, however, the RAM is used for temporary storage purposes, because the info is lost as soon as the power is shut off. When you use a shared web hosting account, the physical memory that your scripts can use may be limited and can change according to what the some other clients on the same hosting server use. With a virtual or a dedicated server, however, you shall have a fixed amount of RAM which won't be used by others even if you don't use it at a given time.