What purpose does the Like button serve? I've never understood it and don't use it.
So back in the old days of forums people used to reply with a "thanks for the info" post or "I agree" or something similar. Things got really cluttered up and the real discussion would get lost. Some forums had a FAQ or forum rules area that would say not to post a "thank you" post for this reason. The whole "like" thing just stemmed from a way to streamline forums without cluttering them up.