Serialized = carry over.
Episodic = No carry over.
It's that simple.
The difference between Scorpion connecting with the Gift, or Day of Honor connecting with revulsion, with every other epiosde underlines exactly how stand alone these stories really were.
Continuity = Stuff form yore reasserts or even flitters.
Your (most inextreme) definition of Continuity = Look it's a Borg story with more Borg, therefore conitnuity! As long as there's a new Borg story every now and then, it proves that there has always been Borg.