RAM, which is short for Random Access Memory, is a computer storage media which could be accessed way quicker than a hard disk, as the info can be read randomly, skipping the bytes before the needed information 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 are able to use, the more applications you'll be able to run all at once and the more people will be able to check out your websites with no effect on the site’s/server’s general performance. Different from a disk drive, however, the RAM is used for non permanent storage purposes, as the info is lost when the power is shut off. In case you use a shared web hosting account, the physical memory that your scripts could use may be limited and might change according to what the some other clients on the same hosting server use. Using a virtual or a dedicated web server, on the other hand, you shall have a guaranteed amount of RAM that will not be used by anybody else even when you do not use it at a particular time.