I just realized, again, that the function of bookmarking services like delicious.com is not to keep interesting links in store, but to make them disappear. It's always pretty much the same sequence of events: I stumble on an interesting writing or page, I realize that I don't have time or the energy to read the thing. So I click the "to delicious" button and I will quite likely never visit that page again. As soon as I click "save", I feel that the link is there safely and I don't have to worry about it anymore. Which in turn means that I forget about it.
Well, sometimes I do end up visiting the page again and sometimes it might be that the only way to find it is through the backlog of links in delicious.com. But for the vast majority of links, these bookmarking applications only serve as graveyards. Bookmark to forget.