RAM, that means Random Access Memory, is a computer storage media which can be accessed faster than a hard drive, simply because the info can be read randomly, skipping the bytes before the needed data 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 can use, the more apps you'll be able to run all at once and the more people shall be able to surf your websites without effect on the site’s/server’s general performance. Different from a disk drive, however, the RAM is employed for non permanent storage purposes, since the data is lost as soon as the power is shut off. If you use a shared web hosting account, the physical memory that your scripts could use may be limited and may change based on what the other customers on the same server use. Using a virtual or a dedicated web server, however, you will have a fixed amount of RAM that will not be used by anybody else even if you do not use it at a certain time.