Sad news, the excellent bookmark sync and bookmark tagging service XMarks (formerly the Firefox bookmark sync plugin foxmarks) is shutting down in Jan. There are alternatives of course, primarily being Firefox Sync, however XMarks stood out by not being just a syncing service, but also suggesting tags for bookmarks and did cross browser syncing to every other browser on earth. I wasn't particularly fond of their "content surfacing" (read: pushing other peoples stuff on me), but that was pretty easy to turn off.
Sadly the blog is down so y You'll have to gleam what you can from the reddit discussions. Ah, blog is back up. Long story short, it's about money, or lack of it.
From the post:
The past four years have been a wild ride for us: growing something from nothing to substantial scale, providing a simple service that people love because it simplifies their lives. We've learned tons along the way, often by making big mistakes. We're really sorry that this last lesson means that you'll have to find an alternative to Xmarks, but the alternatives exist and you'll have no problem finding them.