I'm really interested in Careers, it seems like a very good way to find employers in the field of programming. My question is about using Careers for finding a job in web design, as opposed to web development. Would it be wise to use Careers for that, or is there an alternative better suited for web design?
There's absolutely no harm in having your CV/resume on Careers; it doesn't cost you anything to do. Careers isn't just for programmers. I see some sysadmin and data jobs being advertised. If you're not wanting to be a programmer, though, you should probably expect there to be less jobs in the area you wish to enter.
Which brings me to my next point; if you're looking for a job go out and look. Don't rely on one website, whether it's Careers or your alternative.