It's possible to make a site simpler and more straightforward for users by making it prettier. Really good web design is very subtle; things like giving small but definite visual cues for where posts begin and end, or making the "reply" link a slightly different color from the post so it doesn't look like part of the post -- these small changes do more than look pretty, they also lower the cognitive load on the user and make it feel simpler. A lot of what Reddit has been doing to their interface has been tiny changes that make it feel simpler. Good web design is something to be appreciated; great web design makes you forget that it's even there.