Let's kick off by raising some question directly:

Which kind of posts deserve merits?
Do you send your sMerits to users when you simply agree with their posts?
Do you send your sMerits to users when you diagree with their posts?

There is nothing completely right or wrong in life. What we do believe is right today might turn into wrong one someday later. Nobody knows when current facts turn into wrong ones because all things we cope with are two-sided.

Everyone has rights to present personal opinion, and when people put decent efforts to collect proof (from available statistics), from their own calculation/ estimation, from available high-reputable sources, in order to demonstrate their opinion with good intention (not to make decent works to prove something to scam others), I do believe that their opinion should be respected.

At least, their opinions that reflected via posts (in forum) remind us that there are opposite sides that we should spend our time to reconsider, and recheck our opinion is right or wrong. It's only good, not bad.

Before going to answer three big questions above, I quoted some posts on merit system, how to use merits, from theymos (there are likely more, but I have not found all of them ATM).
In Merit & new rank requirements

Quote from: theymos on January 24, 2018, 11:00:11 PM

I'm hoping that this system will increase post quality by:
- Forcing people to post high-quality stuff in order to rank up. If you just post garbage, you will never get even 1 merit point, and you will therefore never be able to put links in your signature, etc.
- Highlighting good posts with the "Merited by" line.

While we will not be directly moderating this, I encourage people to give merit to posts that are objectively high-quality, not just posts that you agree with.

Quote from: theymos on January 26, 2018, 06:39:42 PM

Please try to merit posts that other people might find interesting, since top-merited posts show up on the stats.

In Writing a welcome message

Quote from: theymos on September 23, 2018, 08:58:25 PM

Merit, which is gained by making good posts.

Quote from: theymos on October 21, 2018, 02:28:55 PM

Aside from that, if people complain about whether things deserve merit at all, then that's something to perhaps think about, but if you conclude that they're wrong, then that's that.

Answers:
* It is not a guide on merit usages, just my opinion.

1. Which kind of posts deserve merits?
Answer: Posts that are objectively high-quality or good quality deserve merits. (Please read theymos's opinion above)
- Which posts are good/ high-quality?
They are posts that on-topics, informative, stay on questions of OPs and other good/high-quality posts in threads. They have to partially (at least) answered questions of OPs or answered other questions from high/ good-quality posts in threads, that gradually popped-up when discussions move further.
Posts are informative, answered OPs' questions are still pointless if questions already answered by previous posts.

2. Do you send your sMerits to users when you simply agree with their posts?
Yes, you can.

However, you should do it wisely, based on quality of posts you agree with. If those posts are high-quality, helpful; I totally agree to send smerits to those posts when you agree with.

It means if you agree with low-quality posts, please don't send your smerits to those posts. It is kind of goes against the core purposes of merits.

3. Do you send your sMerits to users when you diagree with their posts?
Yes, you can.

Once again, whenever a post is high-quality, informative, on-topic, and worth-reading, question-breaking, question-opened (or posts that open the door to discussion as @mikeywith expressed), it deserves merits.
It is so easy to identify such posts by yourself. How?
If you see a garbage-post, you will move on in seconds. Do you agree?
So what if you see a post that catches your attention, and keeps you reading it for a while (minutes or longer), it is a worth-reading post. Even after spending minutes to read and think of ideas inside that post, and finally you disagree with, I do believe that post worths a merit, at least.

Quote from: mikeywith on September 01, 2019, 12:43:20 AM

I recently started focusing on posts that open the door to discussion even if they don't have a direct answer to the problem/question in hand

Some opinions from users

Quote from: LoyceV on August 31, 2019, 07:14:47 AM

Quote from: Welsh on August 31, 2019, 01:31:16 AM

I've personally merited posts which I outright disagree with

I do that sometimes, but it confuses people:

Quote from: akhjob on August 26, 2019, 10:42:54 AM

@LoyceV, meriting/agreeing to the OP from trusted device but disagreeing from non-trusted device Huh

Most people have been conditioned by large corporations to use "Like" and "Upvote", and they're used to it. Merit is different, but it doesn't show when you're meriting a post. Users won't know the difference if they don't read about it on Meta.
I'd say Bitcointalk needs a small explanation on how to use them ("merit good posts") on the "Merit a post"-page.

Merit awarding as an alternative to posting.

Quote from: TryNinja on August 30, 2019, 09:48:04 AM

Quote from: dkbit98 on August 30, 2019, 09:35:36 AM

As I said before ....many users do not have merits.

What about them?

That will only make them more quiet

Merit isnt meant for that anyways. An Agree would be more about pointing out your opinion without you needing to create a redundant post (not necessarily reward a good post). However, Im pretty sure thats not going to happen.

Quote from: NeuroticFish on August 30, 2019, 04:12:19 PM

Merit is indeed for awarding usefulness, not that you agree or like what the poster wrote.

Quote from: suchmoon on August 30, 2019, 04:22:03 PM

Please don't use merits as a substitute for "agree" and don't make "+1" posts.

It's a discussion forum so discuss. If you don't have anything else to add other than "+1" then just don't.

Quote from: LoyceV on August 30, 2019, 09:08:46 PM

I wouldn't do it for posts you "agree with", but for posts that are worth reading. I've done this to posts that stated what I wanted to add to the thread already, so posting it again would be spammy. So I try to highlight the post by Meriting it.
I guess it's caused by actually reading the thread, instead of just responding to the title or OP. I'd say that's a good thing.

Quote from: Welsh on August 31, 2019, 01:31:16 AM

I've personally merited posts which I outright disagree with, and have even merited posts which are wrong. However, if there's a good argument or at least some effort was applied then it doesn't matter whether they get their facts a little skewed. Whoever you are you are not going to have all the answers, and especially when discussing technical aspects of Bitcoin. My merit rewarding system is all about effort, and quality rather than being factually correct.

Of course, if they're spewing total nonsense which makes little sense then that's not likely to get a merit, because its likely not constructive, and a quality post to begin with. An example would be discussion of the conspiracy theory that certain people on this earth are lizards. Even though I think that's batshit crazy if they bring some quality discussion, and reason to believe that then I'll likely reward them for that even though I'm totally against the suggestion as long as effort has been applied, and its of high quality regardless of the subject.

This post is what users discussed a few days before merit system released, but it is worth to note that theymos emphasizes he would prefer users using merits not as Like button (see above quotes).

Quote from: Vod on January 22, 2018, 07:14:18 AM

Quote from: LoyceV on January 16, 2018, 12:31:18 PM

Quote from: Vod on January 16, 2018, 09:15:49 AM

Someone who has time should maintain a list of these phishing sites, and we can encourage all new users to update their hosts file.

Someone already did that: https://github.com/StevenBlack/hosts (scroll down a bit to see many different categories hosts files). The one mentioned above isn't on it though, so I've added it by myself.

^ ^ Another post I wish I could simply +1 or "Like"

Please Theymos..... Grin

I gonna add more quotes.

To end the thread, do you agree with my opinion? Kiss