It only lists things that you are already sharing on sites such as delicious (and only if you add those services). See http://news.ycombinator.com/item?id=6167

It only lists things that you are already sharing on sites such as delicious (and only if you add those services). See http://news.ycombinator.com/item?id=61675 http://news.ycombinator.com/item?id=61675