A few years ago, we had some issues with hosting the Cincom Smalltalk Non-Commercial downloads - the server they were on didn't have sufficient disk space to hold everything, so we got a new one. In order to keep things running, I hacked together a"temporary" application that would keep the downloads flowing.
Well, that temporary application is still running, nearly 4 years later. It was never written to be permanent, and the way data was being stored made duplicate entries pretty much inevitable. Well, today I finally got around to weeding those dupes out - on the live server. If you tried to login or register for the NC in the last little while, you might have gotten an "application maintenance" screen. That's done now, and things are cleaned up.
The lesson? No application is every temporary. Does that mean that you need to do the whole enterprisey design up front and set it to scale to the hilltops? No, but it does mean that you shouldn't have delusions of temporariness, either :)