NEW:
I suggest a "Agree/Like" button. In some situations I find myself no ways to show agreement or likeliness. This would also make this forum clearer.
For example, someone made a thread about their keyboard collection and 4-6 people have wrote "Good collection!
", "Nice collection
". What I would be doing is writing the same thing all over again and feel like I'm spamming. That's why I don't do it. So why not just click a button on his post? If I have more certain things to say, like "Wow your HHKB has great keycaps! Where did you get those?" or even "I wish I was in your place.", I would simply do that.
The same thing is with agreement. I find a constructive and argumentative comment and I don't have anything to add to it. I simply agree to it. Why do I need to quote it and write "I agree", "Exactly!" or even "This!" on top of a bunch of replies that are basically the same?
Doesn't all those same comments look like spam, feels out of context and is hard to read? Isn't a button and a number just an easier and better way to display the same thing? I agree that there aren't a lot of posts like this, but it is exactly what is stopping people from showing what they think.
Now it SHOULD be like this:
1: In my opinion this is wrong, because blah blah and blah blah.
2: Yea, I think the same.
3: Exactly.
10: But blah blah is blah blah blah.
11: Yes, who would think differently.
4. (Quote to 1) I'm with this guy.
Why not do this?
1: In my opinion this is wrong, because blah blah and blah blah. (+7)
10: But blah blah is blah blah blah. (+5)
Did you notice that upvotes doesn't show the same count of how many people agreed to them by commenting? Exactly! People, for example me, don't want to look like spammers, so they simply don't express themselves. It's not just a way to make everything clearer it's a way to make people express them more. I don't see why you wouldn't want that, unless you want to increase your post count.
OLD:
Why there is no button of such kind? You see an useful post, for example review, and you can let the owner know about it with just a click of a button. With this system we could see who brings good content into this community.
Of course, you can write a reply "Good review/explanation/...", but after you see that one person wrote it, you don't want to reply the same again. You also can't check someones profile to see how many people wrote this to him.
There is also an idea that at the end of the year or some other time, we could reward "top x" posters of this community with some geekhack goods. We would not decide who are they by a post count, but by who wrote the most likeable post or who received most likes over that year.
Giving members an incentive to write good content is not the only advantage. If you are in a hurry and want to check a few interesting posts, you could just look how much likeable they are and decide if you want to read it or not.
The only limitation I see is that you shouldn't be able to like a post in "off topic". But maybe there could be more?
I'm very interested to see your opinions about this.