Pinboard is so great. I've bookmarked dozens and dozens of PDF crypto papers, and Pinboard does full-text search across them (and everything else I've bookmarked); I can type "pin subgroup" in my browser bar and poof! I have the paper I was trying to remember that breaks down the known attacks on GCM. To me, it's not "bookmarking" so much as "personal search".
Also, I would pay 2x if it generated more published back-and-forth with the current owners of Delicious.