Big Boards, But not appealing

[mindcry]

I have always thought that the most important thing to having a successful website was not only content, and something that people are interested in, but appealing to the eyes. As at first that is really all everyone sees anyway. First glance and a user decides if they are going to stay if or if they are going to leave.
Anyway, I was browsing big-boards, as of course I have aspirations to be there some day as well I found it rather interesting that most of the sites really weren't appealing at all. The sites seemed very amateur looking. No offense to the guys that made them as they are doing something right because they are huge sites.
I am just rather confused on how they have become so big, yet they are just not appealing to look at.