And this is why everyone should at the very least file down the metal hooks on the usb plugs which hold the plug into the port. If you had, the plug almost certainly would have come out without damaging the port. Of course your N900 would then have hit the floor, but that would most likely only result in nothing more than a few scratches.

I'll admit the hanging thing happened to me a few times with my first N900, when I'd only filed the hooks down a bit, and then the port stopped working after a while but I was fortunate enough for it still to be in warranty at the time and Nokia fixed it, and I also started being a lot more careful and using an external charger as well.

Now all my N900s are out of warranty I have recently got round to soldering the ports down, but I still don't want to hang them by their ports.