Way back in June, Peter discussed KIO, KDE's backend system that applications can use to read and write virtually anywhere. GNOME, with GnomeVFS, provides similar functionality, though admittedly it is lacking in several areas. The project basically was started off on the wrong foot, and it has been a mess from a developer standpoint ever since.
GIO/GVFS aims to fix this. Essentially, it is a GNOME version of KIO, and will be shipped with GNOME 2.22 in March. (Actually, it will be shipped with Glib, which is shipped with GNOME.)
Applications are gradually migrating over from GnomeVFS to this new framework, which is still being developed. Where GnomeVFS fails, GIO/GVFS picks up. One complaint about GnomeVFS is that mount points cannot be accessed by non-GnomeVFS-aware applications. GVFS uses a FUSE bridge to make these publicly accessible. (FUSE, for the uninitiated, is a filesystem that can be run in userspace.)
This FUSE bridge makes it possible for literally any application to use GVFS, even if it is not aware of it. GVFS can mount remote filesystems to a local directory where any application can read or write to them. This makes way for a large amount of possibilities with new applications.
Look for the GIO/GVFS combo to be available in GNOME 2.21 later this year or early next, and a stable version to come with GNOME in Spring 2008.