What are the guidelines of being "cancelled"...???
Here's how I define a canceled show.Any show that is ended by a shows respective network,instead of a shows creator(s),whether it be during the season or at season's end.This would include shows that have running storylines that are left unresolved at the end of the season,and that show is not renewed for a following season.
Shows that are ended by the creators of that particular show,are not considered canceled,e.i. Seinfeld,ER,Friends,Frasier,Everybody Loves Raymond,Alias, and soon to be,Lost.
Shows that finished their season,but were not picked up for a following season,are in essence,canceled.Examples of those shows would be Reaper(which I'm fucking missing a
hell of a lot,pun intended),Jericho(didn't watch it,but from what I understand,there were a lot of unresolved issues),The Unit,Fastlane,John Doe,Terminator:The Sarah Connor Chronicles.
Shows that didn't even get to finish the season,or their network just didn't order anymore episodes to fill the season are canceled as well.Examples: Dollhouse,Bionic Woman,Firefly,pretty much everything that premiered on Fox between 6-8 years ago,like Greg The Bunny.
Now their is some gray area also.A show like Prison Break was announced as canceled,but Fox actually did something good by letting the creators give the show an actual ending,and not just yanking it off the air and having people wonder what the hell happened.I guess technically it was canceled,but the story was over,so I don't really consider it canceled,instead of it just ending.
Anyway,hope that clears it up.