blogs kill groups; cars kill trains; unsustainable ?

Except for the most technical, newsgroups have all migrated to blogs.
So my ISP newsServer is often disabled/sluggish.

When I try blogs, I see that 'the whole book' is transfered back&forth
each time an addition is made. And of course there's no concept of
threading, which gave further specialisation and opportunities for
bandwidth economising.

So then I read about RSS, which 'activates on new/additional stuff'.
But does this allow Txing of only the new material, or is the whole
book still Txed ?

What do they use in China/India ?
I can't believe they'd use such 'convenient'/wastefull methods as
we obsese slobs ?

== TIA.