GNU/Linux is an operating system that runs on personal computers (among other things). Its main technical advantages are modularity, stability, flexibility, and its multi-tasking and networking capabilities. Its main drawback is that it needs care and feeding to achieve its full potential; it is increasingly possible to handle system administration with graphical interfaces (as opposed to typing commands at a prompt), but there are many potential snags that are difficult to fix without some basic knowledge on the user's part. One aim of this note is to provide you, the new or potential user, with enough knowledge to be able to ask questions that will help more experienced users help you, and to help you locate answers yourself in the copious documentation available in a typical modern distribution.
An operating system like Windows 9x requires little maintenance (regular disk defragmenting, possibly re-installation if the registry becomes corrupted), but nothing is very customizable, and you cannot fix bugs yourself. An automobile analogy is often employed in this context: Windows is like a fully automatic car with the hood welded shut; it's easy to drive, and you need not know what happens internally (indeed, you are legally prohibited from finding out). If something breaks, you send it back to the manufacturer and they send you a new one. GNU/Linux, by contrast, requires that you know how to tune the engine at the very least; if you're happy stripping the engine to pieces and rebuilding it to suit your exact requirements, you'll find all the help and support you need provided you know enough to ask intelligent questions. Your car may not come with all the features you want, but you can build and install them yourself. Using GNU/Linux is a fun and challenging learning experience that fosters personal connection to your computer and engenders a sense of community among users worldwide.