RAM, that is short for Random Access Memory, is a computer storage media which is accessed noticeably faster than a disk drive, because the info can be read randomly, skipping the bytes before the needed information is reached. On a server, the RAM is used to load scripts and web programs after they are executed, so the more RAM you may use, the more apps you'll be able to run concurrently and the more people will be able to check out your sites with no effect on the site’s/server’s functionality. Unlike a disk drive, however, the RAM is used for temporary storage purposes, since the data is lost the moment the power is shut off. If you use a shared web hosting account, the physical memory which your scripts could use may be limited and can change based on what the some other clients on the same web server use. Through a virtual or a dedicated web server, alternatively, you'll have a guaranteed amount of RAM that won't be used by anyone else even if you don't use it at a particular time.