There's already enough link rot on the Internet — URL shorteners make otherwise accessible links opaque (you can't tell where they lead), and reduce searchability ("What was that message that suggested example.com?") If you're running your own !SN instance the best way of dealing with URLs is to remove the message size limit and allow URLs of any length. Yes, sometimes you'll include an ugly URL, but that's the fault of that service for not implementing Clean URLs.