Check out this nice write-up on Smartphone RAM over at Android Central. It covers everything from what it is, how it’s used and whether or not task killers are really needed (cliffs notes version: not needed on newer phones with more RAM).

RAM (Random Access Memory) is storage used for a place to hold data.  Think of it as a big filing cabinet that keeps things ready for the CPU in your phone to present it to your eyes and ears.  It’s infinitely (almost) re-writable, very fast, and used differently by different operating systems.  Many of you guys understand what it is, how it works, and what I’m explaining — but we’re going to try and break it down so that more normal and well-adjusted people can follow along.

source:  Android Central