I recently installed Steam on Fedora 18, as the post title implies.
The instructions from sten's ask.fedora post work magnificently...until it tells me that I'm not online:
Fatal Error: Steam needs to be online to update. Please confirm your network connect.
There are a number of awkward fixes like changing a config file that doesn't exist and simply reloading a dozen times. None worked for me, though, so I kept digging until I found Aleksandar30's post that details a snafu in Steam's server configuration in the 1.0.0.39 package Steam was linking to when I wrote this.
I haven't tried removing the
/etc/hosts
line since the Steam client updated.