RAM, that is short for Random Access Memory, is a computer storage media which could be accessed much quicker than a disk drive, 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 programs when they are executed, so the more RAM you may use, the more apps you shall be able to run all at once and the more people will be able to check out your sites without effect on the site’s/server’s functionality. In contrast to a disk drive, however, the RAM is used for non permanent storage purposes, due to the fact that the data is lost once the power is shut off. If you use a shared web hosting account, the physical memory your scripts can use may be limited and might change based upon what the some other clients on the same machine use. Using a virtual or a dedicated web server, however, you'll have a set amount of RAM that will not be used by anyone else even when you don't use it at a given time.