What do Fark, Reddit and Craigslist have in common? These are all sites designed by engineers, not by designers. Yes they have been designed. Even when you think it has not been designed it has. Someone actually designed Craigslist. They just didn’t do the aesthetic planning, visual appeal etc that you did but it was designed none the less.
Craigslist is the example most used when talking about sites which designers would love to redesign yet haven’t risked venturing out to do so. While the visual appeal might be lacking, the experience is great. That’s what the success of a site is attributed to. How often do you go back to a site for its strikingly attractive background? Well yes, hardly ever. It’s the experience that makes you spend that extra time there, bookmark it, revisit it, and recommend it to your friends. The Craigslist experience of being able to go and find that beanbag you wanted to plonk yourself on or to put up a post for a job vacancy is made so simple. This is the experience that drives people back to the site. This experience is independent of the visual appeal of the site.
This doesn't mean that visual enhancements shouldn't be made; there are definitely things that can be done to these sites to increase their usability and effectiveness. But the focus should be on making the site perform better, not on getting it into any design galleries. While working at making interfaces look good, we tend to forget that people use our designs and therefore it's more important for us to design experiences and let the aesthetics work off of the experience that we are trying to create.
Design has always been so much more than coloring in Photoshop. User experience integrates design with psychology, constantly answering many questions. It can be said that aesthetics, usability, functionality and everything that we include in the design process is all part of the experience. Make the experience worthwhile and you can always improve upon the rest later.
What Craigslist offered then in 2007 is the same as what it offers now in 2010. But so long as its experience remains, the design stays invisible.