The site seems simple enough, nice and clean--perhaps too clean.
Before I check out a service, I like to see an "About" link, so I can learn more about the people and company offering the service. Where is the company located? Does it look like it will be around long-term? Who are the people behind it? etc. At the moment, that page has NO information.
Having the ability to create accounts is always nice. That way, users can log into their accounts and maintain their links. I don't see any way of doing that presently. If my favorite forums change from being websiteA.com/forums to forums.websiteA.com, how can I update the alias that was created?
It is also nice to be able to name the shortened URL, to give it an intuitive name.
Google offers their own shortening service (goo.gl) but it doesn't offer this feature either. It does a nice job of shortening URLs, but they are not human friendly; they take the form goo.gl/asddas$3hf which is meaningless. I'd like the ability to name my own slug, for example, goo.gl/mygpluspage
(Unfortunately, Google doesn't offer vanity URLs to the average Google Plus user; users must either use a big long ugly URL, or they have to use a third-party URL shortening service like gplus.to.)
In fact, anybody with a WordPress blog has the ability to have a URL-shortening service too, based on their own domain, with the Pretty Link plugin. And they get to name the slugs, which is sweet.
You are off to a good start. Lots of work ahead of you.