I may just be old and bitter but I've never found emojis to actually help in commentary and are actively distracting when people already have established norms in communicating in a particular language as to my eyes it becomes adding a second language where there was already one. There's no rock solid definition for any emoji that has been normalized with a universally accepted dictionary especially when it is intermixed in another language that has its own complex grammar rules. As a single character statement of a symbol e.g. 'thumbs up' it works well, but that's the limit of emoji usefulness.

As someone who works in tech I'm always aware of the hundreds of completely overloaded terms I have to use and redefine on the fly but I also have the structure of the language I am using to provide context clues to have my actual intent, meaning, and purpose of said writing last to any reader including myself five years from now. I have so little confidence in effectively using emoji to actually provide expression in a way that is persistent to myself in five years that I abstain from it entirely. In small communities of people I have seen emoji-esque symbols exist (slack/forums/odd IRC emoticons) but it is because that is part of the living culture of a particular community and has to be taught to each person that chooses to join a community. I feel that is fine because there is a context to it and an established rule of use that allows it to enrich the conversation, but on a site like HN where it's a lot of people coming together it seems like trying to put a wall up for communication. A simple example is well is most HN commenters fully understanding what a line that starts with '>' usually referring to a quote of a prior post that they want to highlight in particular. It is a useful shorthand compared to writing out longhand 'In your post you have written many things but I particularly want to respond to your comment that reads "x to y".' You have to learn that and it's overhead.

I also depending on theming/font of the emoji characters themselves can sometimes take the wrong tonal interpretation even to me. Some seem sarcastic, some seem more intimate, some seem hostile, even though the underlying emoji is supposed to be neutral in tone. This is another reason why I avoid them, as I don't want to give off the wrong impression based on that.

For a discussion forum like HN I'd say that emojis are generally harmful to making sure that the conversations last longer than the moment they were written in case it becomes useful tomorrow.

I think it falls under the "this is not reddit" mantra which I am okay with. I rather see the type of discourse we have on here than just 1 word / 1 emoji responses.