yum question

[Gerhard Magnus]

> Another suggestion.  I use the yum.conf from www.fedorafaq.org.  It works
> great!  Drop that conf file in /etc and comment out or delete the gpgcheck
> lines (do the same for the files in /etc/yum.repos.d).  Then simply type
> "yum install gmplayer" and it will figure out and install all your
> dependencies as well as gmplayer.
> 
> To whoever said that yum was too slow to use compared to apt, have you tried
> yum-2.1.x (i.e. the yum in FC3)?  It is <tons> better than the yum in FC2
> (2.0.x).
> 
I'd like to start using yum to get software for Fedora 3 and have
replaced the yum.conf that comes with the distribution (backing up the
original first, of course) with the yum.conf from www.fedorafaq.org.
Why is it suggested above to delete the gpgcheck lines in yum.conf and
yum.repos.d?  What do they do?