Isn't the bookmark use case a post-hoc justification of 'like'? It certainly feels like one from my outsider-coming-in perspective.

With regard to the thought experiment of changing the verb to something like "bookmark" or "save", it seems to me that, as long as it's a public action, it would carry the same connotations. In fact I could imagine a world where clients changed the verb to "pericombobulate" and we all started using phrases like "give it a peri" :-)

In the same spirit of thought-exploration, how would use change if the 'like' action simply resulted in a direct message? I.e. have a 'save' action that is private to the user (bookmarking), a 'like' action that is private to the user and the likee (encouraging) and do not provide for cheering.

FWIW, I'm not worried about like-mongering per se, in that this seems like a case of the user also trying to manipulate the medium, instead of only being manipulated by it. It feels more like a distraction, in that the the former does not (can not) significantly compensate for the latter.

You mention decentralization potentially resulting in more fragmentation, but I'm not sure whether you consider that desireable or not.

I ask because the second thought experiment above got me thinking about how lack of 'like' (as it is now) would affect the dynamics of word-of-mouth propagation. On the one hand, popular mouths necessarily act as mediators (which seems less than ideal). On the other hand, to the degree that this popularity is very volatile, this seems like a minimally problematic arrangement.

On the third hand, I wonder if this arrangement is socially harmful as it focuses too much on the person and reproduces the mystical (academic?) practice of speaking in quotations. [Disclaimer: for a few years now, I try to insist that people refrain from using quotations in any discussions I'm part of. Instead, I ask them to try and express any argument they interpret this quotation to be making, in their own words. The idea is that, even when quoting someone is not an outright appeal to authority, it only serves to cloud the discussion by inviting people to come to their own, likely different, interpretations of a quote, transplanted into a different context. This might very well be an elitist position, hence the disclaimer]

Coming back to the point, removing the 'public like' as an option could result in more participatory word-of-mouth propagation of opinions[0]. This would however result in strengthening the role of 'hub' people, so it's not a given that this is an improvement.

[0] Alas, I have to include yet more second-order-effect conjecture here. Even in a medium that allows long-form postings, it is hard to challenge popular wisdom with concision. Requiring that of people might bias the medium in the direction of the echo chamber. So, absolutely not sure about the effects of this thought experiment.