In the case of non-shortening modifiers such as the OP, this can be fixed by using a reversible encoding. (This doesn't address actual shorteners, because of the pigeon-hole principle.) https://blog.osteele.com/2006/04/wideurl/ does this, so even though the referenced service itself is down, encoded URLs can be decoded by hand.

My hosting provider took the service down, IMO justifiably, because it could be used to encode malicious URLs. 2006 was a different time, before it was as obvious that services such as this would be used for this.