Michael at

Counts of likes on different networks might not always be directly comparable to each other

Some networks can talk to each other

eg a like from Friendica or Hubzilla could turn up via Diaspora or GNUSocial

multiple networks can talk Diaspora protocols

multiple networks are rolling out Activitypub,

multiple (and quite a lot of) networks can talk oStatus

and its a good thing that people can communicate between multiple networks!

also there are also quite a few gateways, addons, apps, etc out there where people can connect between their accounts on different networks that aren't currently able to directly talk the same protocols to each other

(and connectors for accounts in proprietry networks also exist out there so even in those you can't always be sure what provided the UI where the user clicked "like")

not to mention also that users could also sometimes use an app which doesn't support like

(and even with a network which does - eg via a "twitter-like" api - apps designed for such api's don't always support like - such as the Pidgin plugin i tried a few years ago)