"Text is a UI
It's a common mistake to think that only full-fledged graphical user interfaces count as interaction design and deserve usability attention. As our earlier research has shown, URLs and email both contribute strongly to the Internet user experience and thus require close attention to usability to enhance the profitability of a company's Internet efforts.
In fact, the shorter it is, the more important it is to design text for usability."
Twitter Postings: Iterative Design (Jakob Nielsen's Alertbox):
