IA: my Bruce Wayne existence
Good IA undergirds everything on a site, from search functions to browsing findability to when and where you encounter the right buttons with the right labels that help you get your task done. That's just the tip of the iceberg, but the typical IA elevator speech is "I restructure your site to help you make a lot more money, and I help reduce calls to your call center."
I do this in bits and pieces sometimes. For example, right now I'm redesigning a checkout process for a huge auto parts store online. I'm also mocking up wireframes for their content management system and redesigning their parts finder. Of course, everything I do is part of a long chain of design, from strategic info planning through to graphic design and technical development.
It's fun to juxtapose my IA skills with the writing I do. (Auto parts guys, have a seat next to Vera Wang and my beauty blogging!)