[quote name='MrX']I started watching Firefly and I have to stay I am crazy addicted to it!! How the

could this have ever been canceled??????[/quote]
General idiocy and happenstance.
The show has gained a following after it's release simply because people have been able to watch it at their own leisure. When a show actually airs, the networks want people to watch from the beginning, to have an audience first. Then once that's established, they keep it going for as long as they can, so long as viewership doesn't completely fall to hell. (see: 7th Heaven/the Simpsons/Law & Order/Home Improvement/CSI/90210/etc.)
If they don't get an audience quick enough they're S.O.L. and sadly a lot of shows slip away due to that, or them not being promoted correctly, or as heavily as was necessary. (see: Dead Like Me, Firefly, Sports Night, Point Pleasant, Dark Angel, Titus, Wonderfalls, Sealab, Clerks, and that's just from my personal little DVD collection)
This is pretty much the case with Firefly. Also FOX decided to F with the actual episode order, and that possibly confused people.