FQDN - why does the problem below arise at all?

I recently installed Mandrake 9.2. Because I run Leafnode, I have
given my computer a fully qualified domain name. In Mandrake, there
is no file /etc/hostname, only /etc/hosts. On this occasion, I
omitted to include the new name in /etc/hosts. This stopped
gtk-gnutella from working properly. The application would open but
not run, and I had to use Ctrl-C to close it. I was wondering
whether there was some problem with a graphics library, until strace
showed that it was trying to connect to my FQDN. Updating /etc/hosts
solved the problem completely. I use KDE, but the same thing happens
with GNOME users who don't do the same.

My question is: why does the program even imagine that it has to
connect to the hostname in the first place? Isn't it just internal
housekeeping?

Doug.