Site is engaging and makes you want to come back to it. Text and background colors do not clash. Information is useful and relevant. Authors communicate a sense of who their audience is. Appropriate and pleasing balance of text and assets.
Linked information is authoritative or illustrative.
Page makes sense and is useful even without accompanying graphics, multimedia, special plugins or browser versions. If the last two are required, the site makes them readily available. Graphics download quickly. Image links and image maps, if used, have a text alternative. Can see meaningful information within 30 seconds.