Basic Considerations

Here are some preliminary thoughts while I work on a more detailed answer.

anti-spam methodologies:
Spammers are a fact of life but there are some things we can do to avoid and/or deter them.

multi-platform and cross-browser compatibility: Sites should be functional regardless of the visitors computer type (pc or mac), operating system (windows, mac os, unix, linux), or the browser they use (Internet Explorer, Firefox, AOL…).

natural/intuitive user interface: The look and feel of each page within the site should be consistent. Menus and buttons should appear in the same place on each page and navigational cues (sometimes called breadcrumbs) should be used to orient the visitor. The design should be easy on the eyes and content placement should flow naturally.