RAM, that refers to Random Access Memory, is a computer storage media which can be accessed noticeably faster than a hard disk drive, due to the fact that 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 applications after they are executed, so the more RAM you are able to use, the more programs you'll be able to run all at once and the more people will be able to check out your websites without effect on the site’s/server’s functionality. Different from a disk drive, however, the RAM is employed for short-term storage purposes, due to the fact that the information is lost once the power is shut off. If you use a shared web hosting account, the physical memory your scripts may use may be limited and might change according to what the other customers on the same server use. Using a virtual or a dedicated hosting server, alternatively, you shall have a guaranteed amount of RAM which won't be used by others even when you don't use it at a particular time.