Picking a font size for the web used to be really easy. 16 points and you’re done. You could feel confident that your content would be decently readable on PC or Mac, Netscape or IE. Man, have times changed.
Typography
What's the Best Font Size For the web? Well, It Depends… — Imarc
Information Architects are the Architects of Understanding. They “help users to understand where they are, what they’ve found, what to expect, and what’s around.”
Information Architecture
Information Architecture (4 Parts) — UX Knowledge Base Sketches