VNC usage

[Peter Easthope <peasthope@cablelan.net>]

Now I have three questions about VNC.

1. The documentation for a VNC client instructs,
"To start a Unix VNC/X-Window server:
  vncserver -geometry 620x730 -depth 24"

Why wouldn't this be started as a background process?
vncserver -geometry 620x730 -depth 24 &

2. Is there any advantage in having each user
start a VNC server?  Why not a system wide VNC
server which starts when the system starts?

3. /home/peter/.vnc/xstartup contains
xrdb $HOME/.Xresources
xsetroot -solid grey
x-terminal-emulator -geometry 80x24+10+10 -ls \
 -title "$VNCDESKTOP Desktop" &

What is xrdb?

4. Rather than invoke the x-terminal-emulator can
the full Xfce desktop be invoked?  If so, how?

Thanks for any answers,     ... Peter E.