It sounds very plausible, from a programmer's perspective.
And yes, sorting and searching would very much need to be a layer on top of the blockchain.
OR, you just search through the entire chain for everything. (truncated of course... you hope)
So, basically building a sorted database as people access information. Is what i picture when i read "hivemind".
... i hope they are not intending to build a permanent database... the resources would get huge.
(and the only way this is not conjecture is to be sitting in Stinc and completely knowing the back end)
@Steemsql and other databases already exist as a database form of the blockchain and I use it for Steemocean.com - but yes, the resource load is high, so I hear.