Per-user E2 theme preferences.
Font information is expressed in CSS terms: 12 pixels is expressed as "12px", 12 points is expressed as "12pt". Font names are comma-separated lists, such as "Helvetica, Arial, sans-serif", where the browser tries to find the first one, then moves on down the list until it finds one that's installed on your computer.
The font-setting bit does appear to have an issue on Linux with Netscape 4 and Mozilla (then again, the Mozilla problem may be fixed now), and also on MacOS X with OmniWeb. If anybody has any insight or educated guesses about what might cause this, I'd love to hear from you.