The first ever Linux distribution I used was not Debian or Slackware but Red Hat Linux. In fact, as I remember it, the version of Red Hat I used was ver 6.2. A couple of years back, Red Hat decided to demarcate its Linux offering into two separate entities namely the free as in beer and Free as in freedom Fedora and its paid version but still Free as in freedom offering namely Red Hat Enterprise Linux. The improvements that are made in Fedora, after they go through a period of severe whetting are eventually incorporated into Red Hat enterprise offering or so it seems.