For most users, the only significant new feature is Charm's support for LiveJournal's tag system.
However, Charm now also works as a client for blogging sites that use the Atom API. That means that if you also blog on Movable Type, Blogger, etc., you can also use Charm as a client for those sites. (Charm also supports Movable Type's categories system in a way similar to LJ tags.)
I've got a backlog of some other stuff to do, processing suggestions and patches from other folks, but I thought I'd go ahead and release this now, since it's been a few months and the current code seems stable.