I agree with @pekka original post:
acknowledge are different. Yet, I’m not convinced it makes much difference in practice.
If Facebook is designing 6 “moods” to replace the unique “like” button, it’s because they’re into the surveillance business, and want to gain value by sorting the emotions of people. But Discourse is a different animal.
In any case, such notification should be voluntary to protect privacy. I don’t know about you, but I’ve never ever sent a reading notification by email. It’s only to relieve the tension of your correspondent, and doesn’t bring anything else than expectation from them.
OTOH I’d appreciate to know when someone bookmarks one of my posts, because it’s meaningful with regard to the kind of stimulation people get from my writing: if they bookmark it, it’s probably because it’s a reference, or because they want to act on it later. But that’s already different from nodding.
I see a couple of options to handle this nodding:
do nothing: let people use to acknowledge and like
ack and change the icon to or something more neutral.
propose a choice of icons, with like as default (i.e., if you click and 1 second passes without more action, it’s a ) and other choices such as , , , , etc.
I’d go for 1 personally (I )
Although 3 sounds “diverse”, I’d recommend against it, because u not want ppl tlkng as if they wrote sms.