Yummy_1A new social bookmarking tool: Yummy!. You can add your own pdf files and tag it. You can search for pdf using the search option or by using the tags. Of course there is the most popular list. And there is an RSS option. But you have to register. It looks a bit like delicious. It is beta and that’s obvious. Some feature do not work. I added some pdfs and that seems to work.