Interestingly, web design entered the mature stage in which not all technical possibilites are demonstrated, but in which the user is in the centre of attention. Matt Cronin wrote an article a while back which is still highly interesting: 10 Principles For Readable Web Typography. His suggestions become ever more important for any software running in a browser, blurring the lines between stand-alone software and a website.
The principles Matt suggests are:
- User-Friendly Headers
- Scannable Text
- White Space
- Density of Text
- Emphasis of Important Elements
- Organization of Information
- Clean Graphical Implementation
- Use of Separators
- Good Margins
Some of them are applications of basic design principles, but nonetheless I agree with all of them.