what is linux

you know, i thought i knew what linux was, i use windows, what is linux, how is it different? why do programmers tend to preffer linux if they do? is it stablity or what?

Ok I'll try to get back to the topic.
Someone mentioned more programmers are working with Windows.
I just have to agree to that. If you just look into the newspapers and see the IT jobs you'll realize that many require .net knowledge but few linux knowledge. This is probably due to the programs they produce. Most programming companys write for users that don't want to think about the memory efficency or how poorly programmed the programm they use is. They write for user that just want to use a simple and easy to learn software.
So why not use .net if you can create the same GUI in half an hour that would take 3 hours to code manually if there would be only a minor spped and memory gain which the end-user would notice(I know there are GUI creation tools for linux as well. I just made an example).
But of course there are areas in programm which require a highly customizable OS. A good example here is science or production-software. For example a robot-arm can't be really be controlled precisely by a Windows machine because Windows lacks  realtime support which would cause a Windows controlled robot-arm to be not synchronised with the other machines.
Also Linux is good for internet hosting or any other server-sided task because "it can be stable".

But I haven't really seen a better-than-Windows desktop-Linux (maybe I just haven't tried out enough distros). In my opinion one of the reaosons for this is the lack of standards. Because if you really need a program and there isn't a package for your distro or package-manager of even worse none at all. You'll have to get the source and install the programm. Sometimes this is really easy but the other times it can be the hell (e.g. other non-packaged dependencies or need of extensive configuration) for people who just want to use the programm and don't want to know how much possibilities there are to customize the programm.
But don't get me wrong I am a helpless Linux fanboy so I see the great potential in Linux for as a desktop-OS but nontheless I have to be realistic and say that users that aren't interested in understanding computers but rather in using them would probably be able to use an already set-up Linux system but I think they sometimes will have a hard time customizing it.