I don't really know anything... thus not answering in the hopes of an sbi share... but to my understanding, an upvote on one platform is the same thing as an upvote on the other... I think that they are just tracking what posts with the proper tags are upvoted for and by who.... then taking that information to figure out how to distribute spt and pal based oh how much of those tokens people have staked. It all still uses vote power and resource credits from your steem account.

Palnet.io and splintertalk.io are basically heavily filtered instances of steem that have their own token economies.

That is how I understand it so far.