1. The landing page does not tell what the service is for and who is it for.
On the first look, it looks like just another URL shortener - but why would I use it over something like 3.ly or j.mp?
2. I tried to read the explanation but bored out. I don't care what "healthy link shortening" is or what rev="canonical" does. The blog post is longwinded and filled with jargon and terms I don't understand. "Publisher"? Am I a "publisher"? Do I want to be? What is the target audience? Am I in the target audience? It's difficult to find out.
3. I put in "google.com" and out comes INVALID_URI.
4. Not having a "Submit" button feels somehow awkward. I'm not sure what I should do in order to shorten the URL. I eventually discovered that pressing Enter and clicking on the "isn't short" text works, but I'd feel better with a "Submit" button.