Apparently the new delicious is not very useful in very many ways, and people are migrating. Many seem to be mentioning Pinboard and Diigo. I've never used Pinboard, but I have used Diigo intensively since 2007. It's a shiny service with a lot of very useful functionality, so much of it that I'm still not sure I can bear to leave it behind completely. (EDIT: Now I'm sure.)
It's not a good port in a storm for fannish bookmarks, though. I'm sure of that much. Of course all bookmarking services have their problems, and I don't mean to blow Diigo's out of proportion - again, the things you can do with bookmarks on that service are pretty amazing, and I'm still half in love with it myself.
But I don't trust Diigo anymore. They have a history of making functions quietly disappear without notifying users or explaining anything (like the full text group search feature which our department's research group happened to rely on, and the auto-post to many other bookmarking services feature that Diigo prided itself on at first and then retired almost completely). My bookmarks export broke down somewhere in 2009. All my requests for help on the support group, where the admins are usually very active, have gone ignored by Diigo staff in spite of other users reporting the same problem and helping me bump the threads.