Originally Posted by BrownLeopard

As a web designer/coder, I'd like to add to this list:
Colors: Earthy tones are the most eye-friendly.
Flash: Worthless. If you have a large mobile crowd, at least have a detection script running with a non-flash area just for mobile users. It's annoying to have to download a huge .swf just because your coder can't be bothered to code a proper CSS nav area. I usually hit this with adblock.
Coding: PHP/MySQL/CSS are your friend. Very dynamic and it keeps things low on the client end since PHP is server based.
Splash pages: make it an automatic re-direct to the home page quickly. If I have to wait more than 5 seconds, I've already closed that tab and moved on.
Embedded music: Get out of the 90's. Embed an mp3 player on the page so the user can choose to listen or not listen. Don't force it on them. That's another thing that gets closed quickly by me.
Great list and rules to live by!