I just checked the users of the posts on the first page. All users that have (almost) no karma have posted junk.
Not all posts by high-karma users are good, but a base level of karma required for posting can't hurt. If somebody does't spend time on the site commenting to archive e.g. 25-100 karma, why should we expect that user to provide a lot of valuable links within the sites focus?
How often do you watch it? It moves faster during the day. There are times where there is more spam than not. And if you feature it on the home page, the amount will only go up.
