OFTEN, I would estimate USUALLY, the overall world is not defined at the start in any great detail. Star Trek, for example, starts in "Where No Man Has Gone Before" and establishes only the existence of the ship, its bridge crew, the existence of a 'United Federation of Planets', and that's about it. A few additional details are established during the episode, that the USS Enterprise is on a long-range exploration mission, that without its warp drive it is decades or centuries of travel time to home, etc. Now, SOME additional things were established by the show's producers by this time, but most of the detailed 'lore' of the milieu was established by writers in their scripts on a weekly basis from whole cloth.
The problem with this is unless all the writing is being done by the same person or very few people (almost never the case in a TV series) or is mostly done as a block ahead of time (e.g. the recent Battlestar Galactica reboot) glaring inconsistencies are going to develop in both the backstory and the ongoing plot, and AFAIC this is unforgivable in what's supposed to be a professionally-written thing even though the end result can still sometimes be entertaining.
X-Files was awful for this - by about season 5 as soon as you saw the writers' credit for an episode you'd know whether that episode would at least try to adhere to established canon and lore or throw it out the window. And don't get me started on Star Wars...
I expect the same would be true for Stargate SG1, etc.
Can't speak to this specific series, as my sum total viewing of it might come to an episode and a half...maybe.
The same pattern holds for other genre. In the D&D cartoon stuff is pretty much established as it happens. Mission Impossible simply created whatever organizations, locations, geopolitical situations, countries, etc. that were required for each week's episode.
Ignoring the bigger picture (overarching plot and-or internal consistency) in favour of the smaller (what's good for this episode), as it were.
I look at it the other way: if the bigger picture is solidly nailed down ahead of time then it'll be much easier for the smaller picture to take care of itself on the fly.
Obviously in an RPG context it can easily work the same way. All that need be established at first is the bare minimum framework to allow for the basic episode structure to be established. The rest will take care of itself. In a Story Now kind of rendition the nature of the episodic format will be partly dictated by the player's stated goals and interests, or perhaps by an overall campaign theme that is agreed on by the participants before it starts. Genre conventions can take care of much of the details, and the rest will come out through play. Each episode would probably address a specific character's or several character's dramatic needs. Judging by the kinds of things seen in the TV shows I mentioned there would likely be existential threats, moral quandries, physical danger, possibly threats to the status quo of the 'team' itself, etc.
One difference between a TV show and a D&D session is that with a TV show it'll be edited down (or up) to fit an exact length of time. In RPG play we don't have that certainty - we don't know how long each session might last and we also don't know how much will get done in any given amount of time within a session.
This difference is big enough to almost make the comparison - not quite meaningless, as there's still something of use in it, but certainly way far from perfect. We can't really look at a session as an episode, for example, as there's no way of knowing whether the plot-of-the-week will be resolved within one evening's play...or, conversely, whether it'll be resolved within a hour leaving the rest of the evening hung out to dry.
One can, however, divorce episode and session. From here, in traditional play one can then look at each adventure as an episode spanning two or ten or however-long-it-takes sessions of play; and [MENTION=82106]AbdulAlhazred[/MENTION] suggests story-now can go the same way only substituting something else for "adventure".
That said, I still don't see any of this as an excuse for internal inconsistency and bad (or no) plot continuity.
Lan-"I wanna be in pictures"-efan