I keep referring to this – the Plan for Availability in Technet. Although it’s the plan for availability, it’s got a good discussion of server topologies.
Quirksmode is a neat little site describing various features and their support across browsers. This is important, in a world of non-standards compliant browsers. For example, I recently discovered in some code of mine that in an event, Opera 8 supports both ‘srcElement’ and ‘target’ properties. In fact, it seems to support both event models. I can see why, but this caused my code (where I set event.target = event.srcElement if event.srcElement existed) to blow up.
Oh, and it neatly describes a problem I found (and had to solve) yesterday with the ‘this’ keyword in event handlers in Internet Explorer. Wish I’d known this before.
Anyway, I like this site, and it is useful.