Search Engines don’t like getting error messages when trying to access a link that was previously submitted to them or indexed for that matter.

Good Quality Anchors will are also important as well as ensuring that linking methods make sense and enhance navigation.

The audience is very important, and depending on how open or closed that audience is, your check list may vary substantially. The more open the audience the more open, browser and bandwidth friendly the project needs to be.

If you are developing for a closed audience and let’s say a web app for a company, whose environment you are sure of or even better, in control of, then you can develop to suite the environment and even consider not supporting certain browsers at all, if it will have an impact on your ability to deliver a faster and more feature rich application.