We're a startup based in the Netherlands and we are building, as a first project, a URL shortener with a catchy name: lnk.je (it literally means: small url in dutch)
We're targeting twitter/fb/hyves users for using our service through our site or API.
Basically: no hard requirements at all. It has to be a 'readable' design which is also easy to transform to smaller sizes (businesscards, favicon, etc etc).
Some 'logic' in the logo is great (linking, urls, shortening).
I like the color blue (soft ones) but it's no hard requirement.