Let's just hope that when they do die, their link database is given to archive.org - http://www.archiveteam.org/index.php?title=URLTeam#Dead_or_B...

URL shorteners are a terrible idea.

URL shorteners are a great idea, but for very limited use cases. I think they only make sense when run by a particular service for use with that service's URLs, like t.co or db.tt, and live and die in tandem with the underlying service.

General purpose URL shorteners are just time bombs waiting to go off. They'll die and break all of their captive URLs or they'll realize they need to make some money and do something like this (or much worse). There's no third option.

Well third party URL shortners can be useful when you are sharing the URL via SMS or an IM, i.e., just for a quick share.