rev=”canonical” is an interesting solution to the problem of URL shortening. It inspects the link you want to shorten. If it finds a “canonical” URL then it uses that. e.g. dopplr.com/along/nested/url/that/needsshortening could specify http://dpl.it/1234 as its canonical/shortened URL.
You still have to ask yourself though if you really need to use a short URL. Most short URLs are no more memorable than the URLs they replace. The only real reason is for space-limited mediums like SMS. Ideally publishing systems should be smart enough to only shorten when necessary.