I worked with it, read about it in so many forums and linux tech docs, never fully understood the potential it possess. Someone while working reminded me again by asking if I am aware about udev, a quick google gave me many pages which understand the concept, and after reading some of them , looks like i never fully understand its capabilities. So, previously there was this /dev directory, which possibly have names for all the devices which possibly might get connected to your system which is running Linux OS, udev essentially helped the developers to stop writing those names in /dev and allowed udev to create device symlinks from SysFS(/sys on most linux systems), which in turn identifies every device connected to the system.
I believe, because it gave flexibility to the HW vendors, and developers to attach any device to any port and have the system display the same name every time when a device is connected to the system, for ex you sony camera would always be named and detected as Sony camera, to whichever port on the system you connect to, unlike previously when pen drives or printers connected to different ports will give different name every-time they are inserted or boots up.
Well, I may not go into the details of configuring and customising , please visit Greg’s Redhat article on udev.