I think it is not necessary because users can withdraw comments anywhere they want, this is their right to use. If you don't like the comment, the post owner can hide the comment. retro bowl

As a side note, I do have a Reply Comment component, I haven't released it yet because I just moved it into the beta testing phase. And, I have plans to fully test it out after I work through the quirks of upgrading from 5.6 to 6.1.
Once I finished getting things hammered out, I'll be free to focus on the tedious task of testing the component to make sure that it works without major errors, and I will be putting it up as my first public ossn component.

As for sub comments I am not willing to work on it is a nightmare as you may seen how much time we spent on fixing notification feature it will be totally mess for sub comments.

When you someone request about feature its might look very simple but we as developer look as a coding side, adding sub comments will require not only one component to change but entire system, it may also require to change all of the comments we have on community which uses comments.

I think with the mentions reply is sufficient, look at reddit for example, its messy and very frustating to see responses or comments, facebook it has only sub comments and is weird.

For now, the best solution is that @Michieal ~ Coder ~ says, a reply button that make the mention automatically.

I just logged into OSSN to see what you are talking about and I agree with you. It's a function that any social media network should have. Linkedin, Fb, and so many others have it. I think it would be something that OSSN has as well. Perhaps a committee of people can come together to develop it as a component, sell it and the proceeds benefit all that worked on it with those working the longest getting a higher part of the percentage. Just a thought.

I've looked into this, and the mechanics of doing subthreads is really hard, messy, and mostly a nightmare.
When I built my ReplyComment component, it would reply to the comment owner but it kept it in the main thread.
More than one or two replies, and the comments should pop over into chat, as that's where it goes tangential to the post / comments. So that's another argument against multi-layered comment threads.
Programming / System wise, there's nothing in place to track the top-most comment that the thread would be linked to and placed under. Meaning that the system would have to be changed in a fundamental way, to store the replies in a thread.

I understand but I think that at least 1 or 2 sub level should be very useful. better that nothing. most of my users write me about this missing function

Sub comments not possible with OSSN and not easily to create such a system Now Facebook sub comments system is so messy if you have a comment somewhere deep inside someone comment you can not able to view it easily.

this is examole on FB member comment a post and other member send answer to this comment and any one can answer to any further sub comment. this is a really big missing feature for OSSSN
or maybe already exist some component that allow to do it?