The past couple of years saw a great proliferation of bookmarking applications.
Of course del.icio.us has been around for a few years. It even seems to have changed its name to delicious.com.
Then I tried ma.gnolia. Actually I'm never sure where that goddamn period goes. That alone turns me off from using it. I don't know why they would go out of their way to come up with such a difficult-to-remember-precisely name. Unless they are exceptionally good, it's just suicide on their part. And I wouldn't characterize it as exceptionally good.
I have yet to really get into the idea of sharing bookmarks. They seem a bit personal to me.
So the main thing I use is Foxmarks, without sharing.