The beauty of open-source software is that anyone is allowed to offer something to the community catering to specific group of users with similar needs. To testify this, there are currently 600+ Linux distributions available now in a wide variety of shape, size and forms ranging from fully featured environments catering to specific needs for desktop, server, laptop, netbook, mobile phone, and tablet computing as well as numerous embedded environments. Amazingly all this started and is built on top of the Linux kernel, click the interesting graphic below to see full-scale version of "The Evolution of Linux Distribution Timeline".