I found bookmarks I've added into Diigo recently weren't saved to Delicous. I've started Delicious saving at "Save Elsewhere". I'm sure the there is no problem with my Delicous account because I've successfully imported some Bookmarks from Delicous lately.

I'm wondering whether this is a temporary problem.

I found we can add tags and descriptions to a bookmark when clicking "Bookmark and Highlight". If we just Highlight something, the bookmark saved would not have any tag and description. I think this is the difference.