I've seen a lot of terminal emulators as a programmer - PuTTy, Gnome Terminal, KDE Konsole, Terminal.app, iTerm, etc.
Someone showed me an 'xterm' for the first time today. I've used these other terminals extensively, but I'm curious as to what unique advantages or features that 'xterm' would offer over any other terminal emulator. That is, what can it do that other terminal emulators can't?