Yeah - I keep thinking of it as "Open" and "Closed" universes. With SW and HP being very much in the "Open Universe" category - simply because there is just so much room to play in. And a show like The Wire being in the "Closed" category for the opposite reasons. These are just work definitions mind, and not rigid categories either. For instance George RR Martins "A Song of Ice and Fire" (which you should read I might add) isn't entirely closed, but it's more Closed than Open.
If that makes any sense?

(now this is just meta in progress, so please help me out here. ;D)