How to Choose Colors for Web Design

One of the real (unfilled) market niches in web design is a designer that knows how design affects conversion -- ecommerce conversion, lead gen conversion, home page bounce, etc. When I hire someone to design a website, I'd love it if they were aware of the following sorts of considerations, and had well-grounded opinions on how to use design to address them:

• How different colors encourage or discourage people from buying, or even from sticking around for a second click.
• How images (of people, of products, of pets) affect whether people will buy, register for my site, click on a link.
• How design affects download time for webpages, and how download time affects people's willingness to stay on a site.
• How a/b or multi-factorial testing works, and why that matters for a designer.
• How to balance the SEO value of actual text, vs the "it looks pretty" value of images of text.

And there are a thousand more issues like this. None of the designers that I've ever worked with have ever even thought these issues were important, much less thought that they were a fundamental part of their job.

Anyway, end of rant. But here's a useful article that talks about some of the implicit meanings of color.