Well, 99.9999999% of forums i see all have like buttons.
And how is it "self gratification"
Because it invites people to post in order to get a lot more likes rather than to answer the actual post.
Then it become competative like "who has the most Farce Book Friends" and starts to imply a correctness in numbers so a wrong reply with a lot of likes gets considered as a gospel truth.
Search engines use the "like" feature to rank searches so in place of finding the answer you wanted you get the responses with the most key words & likes.
A LIKE function is part of the soft wear package and Microsloth were the first to use it.
As to weather the forums you visit has it or not, it is just random as to what package they are using I run 3 and we do not have likes at all.
Further more a response must have a minimum of 10 words in it.
This keeps the responses down to those who are actually answering the question or questions that arose from the original question.
Mission creep is oft quite interesting even if it strays a bit off topic.
Go over to My Tractor Forum and try to follow a thread.
one question , 3 appropriate answers and 15 pages of "Me Too's" which makes it hard to follow a topic.
There is a sort of unoffical proticol that happens here and perhaps you have noticed that only 1 tech answers a question in most cases.
We tend to let them sit for a while to allow every one to post a solution then if needed jump in.
Thus people like Engine man, Rivets, Ilengine, Renyolson, Mechanic Mark, Tinker etc rarely post on the same thread ( sorry for the others that do not come to mind right now ).
Retirees with nothing to do with their time , like Boo seem to want to respond to everything which would be fine if he remembered we are not the grandkids , limited them to text and stopped pasting in all the silly images.
OTOH his searches are getting better.
A part of adding Likes is also adding Dislikes and once you do that you invite trolls .
You also bring in emotions, some of which can be very strong,
The NRA poll is a good example as there are people who believe the NRA is up there right next to St Peter at the pearly gates and others who believe that are the devil himself walking the earth.
So one side sees it as their partiotic duty to dislike every post every person made who did not praise the NRA and of course the other side then feels duty bound to do the opposite.
Look at all the "Don't buy ( insert any brand you like ) because they are all junk" posts that turn up because some one feels agrieved.
If you follow all of the new posts you will see about 1/2 of these posters will go through the archives and post a disparaging remark about that product or company even if they are 10 years old.
Then because you Disliked my post I feel I have the right to respond and very soon the forum ends up worse than Twatter as you defend your position & I counter you defence and on & on it goes.
Without Likes & dislikes posts stand upon the merit of what is on the page and not what "SCORE" it got
Thus people have to look at what is written and make a decision for themselves which is how it should be.