I can give you an answer for 12.04, although this may not be a totally definitive list of protocols. Before we start discussing the protocols, here is a quick summary of the nature of
Gvfs is a userspace virtual filesystem designed to work with the i/o
abstractions of gio (a library availible in glib >= 2.15.1). It
installs several modules that are automatically used by applications
using the APIs of libgio. There is also fuse support that allows
applications not using gio to access the gvfs filesystems.
The gvfs model differs from e.g. gnome-vfs in that filesystems must
be mounted before they are used. There is a central daemon (gvfsd)
that handles coordinting mounts, and then each mount is (typically)
in its own daemon process (although mounts can share daemon process).
A lot of the supported protocols are listed in the
gvfs-backends package and the tools you can use with those protocols are listed in the
gvfs-bin package, which if you have them installed are available by right clicking the package in
Synaptic and clicking on installed files to show the list.
Comparing the gvfs-backends package description and the list of installed files in
Synaptic comes up with the following list.
archive:// archive files support
afp:// Apple file protocol support
afc:// access mobile devices such as iphone and ipod Touch
cdda:// audio cds support
cifs:// communicate with cifs servers
dav:// (webdav://) handles remote filesystems
file:/// access a local file, for example,
ftp:// access and use ftp server
gphoto2:// PTP camera and MTP media player support
http:// open http resources
https:// connect securely with https
obexftp:// bluetooth support
smb:// communicate with samba servers
ssh:// connect securely to server
sftp:// send files securely via sftp
usb:// mount a usb device directly, for example,
This is just a bare list; to do something with these protocols you can use the
gvfs tools on the command line such as
gvfs-mount. The tools are listed in the
gvfs-bin package at Ubuntu packages and in
Synaptic if installed. Basic examples from the command-line are:
The first example will open you home folder in your default file browser; the second will open askubuntu in your browser.
For examples to do with remote filesystems, see this article.
As this answer was not supposed to go into detail on how to use the protocols, I won't go into great detail here, as there are other
gvfs articles on this site.