The other day quoting a post stopped working. When I'd hit the quote button to quote a post I'd get a blank compose window. If I'd post, no quoted test appeared. The only event I know of that might have triggered it on my end is a Firefox update (to 23.0.1). It may be related to plugins. I've had it work a couple of times, including once in safe mode (no add-ons), but don't have it solved yet.